Currently, when gs_offloader fails to offload a job directory,
it continues to track the job, and periodically retries the
offload.  The number of failed jobs being carried is reported
in the gauge chromeos/autotest/gs_offloader/failed_jobs_count.

We should include this metric on the GS Offloader dashboard:
    https://viceroy.corp.google.com/chromeos/gs_offloader