CBQE-0: changes in incremental_rebalance_in_out_with_mutation_and_expiration

Change-Id: Iba48aebd36e1b1ad49240a4b56cadfd678b0b938
Reviewed-on: http://review.couchbase.org/27847
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>