CBQE-0: adjust check for check_ep_items_remaining

Change-Id: I4d3cec8f5d58cbf99d2896896774464a5e8f7ff9
Reviewed-on: http://review.couchbase.org/43866
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Thuan Nguyen <soccon@gmail.com>