CBQE:0 Remove validate_last_checkpointed_seqno method. The logging has changed, failing all tests

Change-Id: I5ae6f246dc8c1d79505edba79353e8b127e821ec
Reviewed-on: http://review.couchbase.org/39501
Reviewed-by: Aruna Piravi <aruna@couchbase.com>
Tested-by: Aruna Piravi <aruna@couchbase.com>