CBQE-2329 :: Add negative tests :: Rebalance and failover

Change-Id: I75d745db762fcac1eac55110be1814ec3948c86e
Reviewed-on: http://review.couchbase.org/39909
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>