CBQE-0: fix failover tests

Change-Id: I2f030cfe9fe4aca61e32238edf33fdb7def7fc86
Reviewed-on: http://review.couchbase.org/37813
Reviewed-by: Ashvinder Singh <ashvinder@couchbase.com>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>