b=21828 drop number of active requests when queued for recovery

b=21828 drop number of active requests when queued for recovery

Now that we take a reference on the original request instead of
making a copy of it for recovery.  We need to drop the number of
active requests or the queued requests will prevent all request
processing when they exceed (srv->srv_threads_running - 1).

 i=nathan.rutman
 i=tappro