CBQE-0: fix TAP failover tests for 3.0.0 and rebalance in test with ops testcase

Change-Id: Ic6a099ac089c99248f3c9f0b30e508c32943a7ec
Reviewed-on: http://review.couchbase.org/36944
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>