Remove misleading log statements

The "adding change" info-level statements more correctly describe
'asking a pipeline to consider adding a change'.  The pipeline
manager already has such a message at debug level, so remove these
in favor of that.  Change the message that actually *does* mean
'this change was really added' to info level.

Change-Id: I11bf260c070ff02b59648cdba20688d342bade24
2 files changed