MB-11497: add wait timeout in incremental_rebalance_in_out_with_mutation_and_deletion

to investigate test is stuck in
http://qa.sc.couchbase.com/job/centos_x64--108_00--Rebalance-In-Out/14/consoleFull

Change-Id: I72472c0d0d551dc688b5c9b395ce9f8ef1bdbbe4
Reviewed-on: http://review.couchbase.org/38646
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>