fix Go SDK codegen for devtestlabs package-2018-09

[jhendrixMSFT]

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[AutorestCI]

Automation for azure-sdk-for-js

Nothing to generate for azure-sdk-for-js

[AutorestCI]

Automation for azure-sdk-for-java

Nothing to generate for azure-sdk-for-java

[AutorestCI]

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[AutorestCI]

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[AutorestCI]

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[jhendrixMSFT]

Fixes #4105

[AutorestCI]

Automation for azure-sdk-for-go

The initial PR has been merged into your service PR:
Azure/azure-sdk-for-go#3622

[azuresdkci]

Can one of the admins verify this patch?