resource/cloudflare_ruleset: Yet Another tristate bool fix

[jacobbednarz]

Updates the check for whether or not to populate the enabled flag on
category/rule based overrides to use the GetOkExists method (not
recommended due to undocumented edge cases) to check the existence
before converting the pointer to a value.

Closes #1403

[jacobbednarz]

acceptance tests (including the updated one) are all passing

TF_ACC=1 go test $(go list ./...) -v -run "^TestAccCloudflareRuleset_" -count 1 -parallel 1 -timeout 120m -parallel 1
?   	github.com/cloudflare/terraform-provider-cloudflare	[no test files]
=== RUN   TestAccCloudflareRuleset_WAFBasic
=== PAUSE TestAccCloudflareRuleset_WAFBasic
=== RUN   TestAccCloudflareRuleset_WAFManagedRuleset
=== PAUSE TestAccCloudflareRuleset_WAFManagedRuleset
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASP
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASP
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryAndRuleBasedOverrides
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryAndRuleBasedOverrides
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
=== RUN   TestAccCloudflareRuleset_MagicTransitUpdateWithHigherPriority
    provider_test.go:160: Skipping acceptance test as 0da42c8d2132a9ddaf714f9e7c920711 is not configured for Magic Transit
--- SKIP: TestAccCloudflareRuleset_MagicTransitUpdateWithHigherPriority (0.00s)
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
=== RUN   TestAccCloudflareRuleset_RateLimit
=== PAUSE TestAccCloudflareRuleset_RateLimit
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIPath
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIPath
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIQuery
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIQuery
=== RUN   TestAccCloudflareRuleset_TransformHTTPResponseHeaders
=== PAUSE TestAccCloudflareRuleset_TransformHTTPResponseHeaders
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
=== RUN   TestAccCloudflareRuleset_TransformationRuleRequestHeaders
=== PAUSE TestAccCloudflareRuleset_TransformationRuleRequestHeaders
=== RUN   TestAccCloudflareRuleset_TransformationRuleResponseHeaders
=== PAUSE TestAccCloudflareRuleset_TransformationRuleResponseHeaders
=== RUN   TestAccCloudflareRuleset_ActionParametersMultipleSkips
=== PAUSE TestAccCloudflareRuleset_ActionParametersMultipleSkips
=== RUN   TestAccCloudflareRuleset_ActionParametersOverridesAction
=== PAUSE TestAccCloudflareRuleset_ActionParametersOverridesAction
=== RUN   TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
=== PAUSE TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
=== RUN   TestAccCloudflareRuleset_AccountLevelCustomWAFRule
=== PAUSE TestAccCloudflareRuleset_AccountLevelCustomWAFRule
=== RUN   TestAccCloudflareRuleset_ExposedCredentialCheck
=== PAUSE TestAccCloudflareRuleset_ExposedCredentialCheck
=== RUN   TestAccCloudflareRuleset_ConditionallySetActionParameterVersion
=== PAUSE TestAccCloudflareRuleset_ConditionallySetActionParameterVersion
=== CONT  TestAccCloudflareRuleset_WAFBasic
--- PASS: TestAccCloudflareRuleset_WAFBasic (11.75s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIPath
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIPath (11.38s)
=== CONT  TestAccCloudflareRuleset_ConditionallySetActionParameterVersion
--- PASS: TestAccCloudflareRuleset_ConditionallySetActionParameterVersion (20.25s)
=== CONT  TestAccCloudflareRuleset_ExposedCredentialCheck
--- PASS: TestAccCloudflareRuleset_ExposedCredentialCheck (10.42s)
=== CONT  TestAccCloudflareRuleset_AccountLevelCustomWAFRule
--- PASS: TestAccCloudflareRuleset_AccountLevelCustomWAFRule (13.06s)
=== CONT  TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
--- PASS: TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride (10.56s)
=== CONT  TestAccCloudflareRuleset_ActionParametersOverridesAction
--- PASS: TestAccCloudflareRuleset_ActionParametersOverridesAction (10.96s)
=== CONT  TestAccCloudflareRuleset_ActionParametersMultipleSkips
--- PASS: TestAccCloudflareRuleset_ActionParametersMultipleSkips (12.38s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleResponseHeaders
--- PASS: TestAccCloudflareRuleset_TransformationRuleResponseHeaders (11.04s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleRequestHeaders
--- PASS: TestAccCloudflareRuleset_TransformationRuleRequestHeaders (11.98s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination (10.61s)
=== CONT  TestAccCloudflareRuleset_TransformHTTPResponseHeaders
--- PASS: TestAccCloudflareRuleset_TransformHTTPResponseHeaders (9.69s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIQuery
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIQuery (13.79s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip (10.52s)
=== CONT  TestAccCloudflareRuleset_RateLimit
--- PASS: TestAccCloudflareRuleset_RateLimit (10.82s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging (10.96s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides (10.74s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryAndRuleBasedOverrides
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryAndRuleBasedOverrides (11.77s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip (11.58s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60 (10.96s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple (11.37s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1 (10.85s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASP
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASP (10.86s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRuleset
--- PASS: TestAccCloudflareRuleset_WAFManagedRuleset (11.12s)
PASS
ok  	github.com/cloudflare/terraform-provider-cloudflare/cloudflare	279.679s
?   	github.com/cloudflare/terraform-provider-cloudflare/tools/cmd/changelog-check	[no test files]
?   	github.com/cloudflare/terraform-provider-cloudflare/version	[no test files]