GCS allows only 1 write/s per key

[trinity-1686a]

Per GCS documentation, we may not write an object more than once a second. For most objects, we never write more than once, but for the metastore, we may update it more frequently than that, which causes errors. We should make sure we retry in this case, and that we don't increment error metrics if the retry succeeded

[trinity-1686a]

retry is now implemented. Keeping the ticket opened there for a future where we may batch metastore writes