CBQE-0:: fix hanging rebalance-out tests

Change-Id: Ib09ee90fbcd60f9a047b2fe41548fe694bd0d7f0
Reviewed-on: http://review.couchbase.org/41215
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>