CBQE-0 :: fix delta recovery bucket verification logic

Change-Id: I947d8f5d9df317c29705c5f1f294212a39fabf80
Reviewed-on: http://review.couchbase.org/39140
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>