CBQE-1141/CBQE-1142: Cbrecovery tests

- Revised verified cbRroutines
- Added test case for failover and addback

Change-Id: Ie9f3c9f5d58a51a5b0421ee43a8ae92f9209ebfe
Reviewed-on: http://review.couchbase.org/26019
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>
Tested-by: abhinav dangeti <abhinav.dangeti@gmail.com>