[autoroll] Fix incorrect success notification
[autoroll] Fix incorrect success notification

If the CQ failed but no trybots were run, we were sending a success
notification even though the roll failed.

Bug: skia:
Change-Id: I1417a3e890a445ef98f12336e02cbce564a36446
Reviewed-on: https://skia-review.googlesource.com/131149
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@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