CBQE-0: fix failover negative tests

Change-Id: Ib4c9a189aa514a0b9c66b2117b5d8fb26ccfaa98
Reviewed-on: http://review.couchbase.org/34980
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>