CBQE-1695: added code to wait for mutation to be replicated

Change-Id: I4e4d9d39ff18f155e5915c7a61078ca7724ad565
Reviewed-on: http://review.couchbase.org/30755
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>