The send complete for RC QPs mismanages the ack count when the
responder side is only in RTR.

A QP in that state cannot send requests, but it can be the target
for operations that elicit responses.

Adjust the RC completion logic to correct the count maintenance
by reflecting RECV_OK in a new state test.
Reviewed-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>