CBQE-0:fix failover test cases

Change-Id: I787ad51bdab4a9f5ab84c40665d3f5aa478b68b9
Reviewed-on: http://review.couchbase.org/37158
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>