fix metadata_startup_script

[edwardmedia]

Fixes hashicorp/terraform-provider-google#12776

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Release Note Template for Downstream PRs (will be copied)

compute: fixed the error when `metadata` and `machine_type` are updated while `metadata_startup_script` was already provided on `google_compute_instance`

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[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

Terraform GA: Diff ( 2 files changed, 67 insertions(+), 2 deletions(-))
Terraform Beta: Diff ( 2 files changed, 67 insertions(+), 2 deletions(-))
TF Validator: Diff ( 3 files changed, 8 insertions(+), 5 deletions(-))

[modular-magician]

Tests analytics

Total tests: 2250
Passed tests 2007
Skipped tests: 241
Failed tests: 2

Action taken

Triggering VCR tests in RECORDING mode for the tests that failed during VCR. Click here to see the failed tests

TestAccFirebaserulesRelease_BasicRelease|TestAccComputeInstance_metadataStartupScript_update

[modular-magician]

Tests passed during RECORDING mode:
TestAccFirebaserulesRelease_BasicRelease[Debug log]
TestAccComputeInstance_metadataStartupScript_update[Debug log]

All tests passed
View the build log or the debug log for each test

[roaks3]

This looks great! I had one question on the tests, and also I think the CHANGELOG entry may need to be compute: ..., not computer: ....

[edwardmedia]

CHANGELOG updated as you pointed out. Thanks

[roaks3]

LGTM, adding Stephen for follow-up review

[melinath]

@edwardmedia it looks like the test is not exercising the changes to metadata.go.erb - that is, metadata.startup-script isn't being set in the test. Would it be possible to add a new test that does a series of updates that transition from using one to using the other?