syncop: synctask shouldn't yawn, it could miss a 'wake'

        Backport of http://review.gluster.org/5058

Change-Id: I7731fd33ca0c925cc52f8d105275b44fc625a1e2
BUG: 948686
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/5071
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>