[CT] Delete swarming bots on startup as well
[CT] Delete swarming bots on startup as well

Bug: skia:7900
Change-Id: I9f4142a6114788f30d72cbed90226394ac7fdd20
Reviewed-on: https://skia-review.googlesource.com/129925
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>
Commit-Queue: 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