[perf] Fix backup cronjob.
[perf] Fix backup cronjob.

Change-Id: I9938fa94f6fb075e705d406933952e73d4903012
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/528641
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@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