CBQE-2212:: Implement couchstore/file level verification of persistence

Change-Id: I88b92dca96b2608d0b7675eb098017c1a4b7cb4b
Reviewed-on: http://review.couchbase.org/37424
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>