DS Backup - Change how backups are named.
DS Backup - Change how backups are named.

Change-Id: Ife407048202e1c20a444404ce89bc3b06a5cd8eb
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/246006
Reviewed-by: Ben Wagner aka dogben <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot