Disable checkpoint.

We don't need to reach out to checkpoint when running tests, so disable
that information. Fixes #640.

Also remove our logging override, as we've updated to a version of
go-plugin that doesn't require that anymore. See also #661.

helper/resource/plugin.go

@@ -36,6 +36,9 @@ func runProviderCommand(t testing.T, f func() error, wd *plugintest.WorkingDir,
 	// plugins.
 	os.Setenv("PLUGIN_PROTOCOL_VERSIONS", "5")
 
+	// Terraform doesn't need to reach out to Checkpoint during testing.
+	wd.Setenv("CHECKPOINT_DISABLE", "1")
+
 	// Terraform 0.12.X and 0.13.X+ treat namespaceless providers
 	// differently in terms of what namespace they default to. So we're
 	// going to set both variations, as we don't know which version of
@@ -100,10 +103,6 @@ func runProviderCommand(t testing.T, f func() error, wd *plugintest.WorkingDir,
 			},
 		}
 
-		// plugin.DebugServe hijacks our log output location, so let's
-		// reset it
-		logging.SetOutput(t)
-
 		// when the provider exits, remove one from the waitgroup
 		// so we can track when everything is done
 		go func(c <-chan struct{}) {