Remove low-value logging from publication codepath

Previously, the pipeline publish codepath emitted log messages
with almost no diagnostic value other than a "comfort bump".
However the sheer volume of these message was overwhelming
logstash in the CI gate.

We remove the worst offenders from that codepath.

Change-Id: If630593e8f755ccc1ede16941459daac30d284ff
Closes-Bug: #1328596
Merge "Remove low-value logging from publication codepath"