The loop over the messages didn't early-exit when it found
a non-CQ message, so it would continue looking until it
found any message by a non-owner. So all CLs with any comments
by anyone other than the uploader would be in 'reply' state
forever.

This CL fixes that, and also makes some other tweaks to
make the gerrit status code simpler and faster.

Bug: 706460
Change-Id: I5cc06962f5121fe042a315e5e2e205e556eb85da
Reviewed-on: https://chromium-review.googlesource.com/470586Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>