[google3 autoroll] Look for successful rolls in UpdateStatus
[google3 autoroll] Look for successful rolls in UpdateStatus

The roller is currently in a weird state where it thinks that there are
42 failed rolls and it's 53 commits behind when there was recently a
successful roll and it's only 6 commits behind. I am not able to repro
this in a unit test, but I'm proposing this change as a speculative fix.

Change-Id: I5a39536744f795a631119067b4e4530fe38b432a
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/198284
Reviewed-by: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Commit-Queue: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@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