CBQE-0 :: fix failing rebalance test case due to change in param name

Change-Id: I7ba4f1edf912245d01f4bceb9f622f22f59e4518
Reviewed-on: http://review.couchbase.org/39740
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>