qa/workunits/rbd: wait for replaying status in bootstrap tests

qa/workunits/rbd: wait for replaying status in bootstrap tests

wait_for_replay_complete() doesn't wait for image status to get
updated.  This didn't matter previously because these tests are run on
two different pools and nothing else was following.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit d1d848276f0a33b20482321088c8c7470a84d0b3)

Conflicts:
	qa/workunits/rbd/rbd_mirror_bootstrap.sh [ commit 3fd8a0388735
	  ("qa/workunits/rbd: merge journal and snapshot test scripts")
	  not in quincy ]