Make the build pipeline fail if cannot post Checks feedback
Make the build pipeline fail if cannot post Checks feedback

When Gerrit isn't able to respond successfully to a Checks API
feedback, there is no value in trying to trigger a build step
because it won't be able to provide any feedback to Gerrit.

At the moment the Checks status remain in "Scheduled" status
and it would be up to the Gerrit Code Review plugin to
re-trigger a build if no other builds are running for it.

Bug: Issue 12598
Change-Id: I04d178e7452fcebf1fbc67582bc6243ab07e9a79

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