CBQE-0:break rebalance conf into smaller jobs

Change-Id: If795807a30a3bb19db26cc4f17ca954e912e9b8f
Reviewed-on: http://review.couchbase.org/36562
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>