CBQE-0: cbtransfer comparison should support back up as well

Change-Id: Ibcbb64c52148fa6e05ca7b684bacaa2510b89d54
Reviewed-on: http://review.couchbase.org/36872
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>