[machines] Always sent PubSub event even if interrogation fails.
[machines] Always sent PubSub event even if interrogation fails.

Change-Id: I6c100ab1abf54e907612a9f6b12141b2e0504020
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/493036
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