Ticket 48767 - flow control in replication also blocks receiving results

Bug Description: In ticket 47942 a flow control was introduced to reduce
                 the load of a replication consumer.  It adds some pauses
                 in the asynch sending of updates.  Unfortunately while it
                 pauses it holds the reader lock, so that the result reader
                 thread is also paused.

Fix Description: If we need to pause the sending of updates then also release
                 the Result Data lock so the reader thread is not blocked.

https://fedorahosted.org/389/ticket/48767

Reviewed by: nhosi(Thanks!)

ldap/servers/plugins/replication/repl5_inc_protocol.c

@@ -479,9 +479,11 @@ repl5_inc_flow_control_results(Repl_Agmt *agmt, result_data *rd)
     if ((rd->last_message_id_received <= rd->last_message_id_sent) &&
         ((rd->last_message_id_sent - rd->last_message_id_received) >= agmt_get_flowcontrolwindow(agmt))) {
         rd->flowcontrol_detection++;
+        PR_Unlock(rd->lock);
         DS_Sleep(PR_MillisecondsToInterval(agmt_get_flowcontrolpause(agmt)));
+    } else {
+        PR_Unlock(rd->lock);
     }
-    PR_Unlock(rd->lock);
 }
 
 static int