Do not allow 0 update rate

apps/openmw-mp/MasterClient.cpp

@@ -152,6 +152,7 @@ void MasterClient::Update()
         {
             LOG_MESSAGE_SIMPLE(Log::LOG_WARN, "Update rate is too low, and the master server has deleted information about"
                     " the server. Trying low rate...");
+            if((timeout - step_rate) >= step_rate)
                 SetUpdateRate(timeout - step_rate);
             update = false;
         }