Change message comment is now published as patch set level comment.
However, comment-added event wasn't extended to reflect this transition.
As the consequence some CI integrations, most notably Jenkins Gerrit
Trigger plugin and Zuul, are missing the comment content and thus the
build cannot be re-triggered with "recheck" or "reverify" change message
comment.
To rectify, introduce new configuration option that is enabled per
default to publish patch set level comment.
Bug: Issue 13800
Change-Id: I668029af2d971c88f157b237bc76b9878e751579
d14db1f2cc