CBQE-1902: add test recovery_when_rebalance

Change-Id: I65f143064474b5f353d9f9a797a1164aba621837
Reviewed-on: http://review.couchbase.org/33384
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>