SAT>IP: do not send signal status packets on shutdown

src/input/mpegts/satip/satip_frontend.c

@@ -1151,6 +1151,9 @@ satip_frontend_input_thread ( void *aux )
                               &sb, 0, NULL, NULL);
   }
 
+  /* Do not send the SMT_SIGNAL_STATUS packets - we are out of service */
+  gtimer_disarm(&lfe->sf_monitor_timer);
+
   sbuf_free(&sb);
   udp_multirecv_free(&um);