features/changelog: fixes when enabling changelog

Other enhancements being:
      * ignore fops made by rebalance
      * ignore internally triggered fops

BUG: 987734
Change-Id: I7dd164ae3c209fdb8ec43a27e67b8846f937c93b
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/5380
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>