gsutil mv sometimes exits with error status when operation was successful.

In the last month or so with about 86k uploads we've had 2 scenarios where a mv of a single small file to a bucket was successful but exited non-zero. 2 out of 86k isn't horrible but the only way to avoid this issue is to hack something together that looks to see if the file really exists after a non-zero exit. Since these operations cost money its a bug that needs to be resolved.

Start with the gsutil mv command described in the report and reproduce a single small-file move while checking both the bucket result and process exit status. The issue names no source file or test; done means a successful move consistently exits with status zero, including under the reported conditions.

Written by the indexing model from the issue text.