Really fix the builderComments race in Status
Really fix the builderComments race in Status

BUG=skia:

Review-Url: https://codereview.chromium.org/2169943002

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