freetdm: fixed no ACM/CPG sending in some situations after native bridge

- clear up ACM_SENT & CPG_SENT flag in DOWN state in native
           bridge state machine

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_main.c

@@ -997,6 +997,9 @@ static ftdm_status_t ftdm_sangoma_ss7_native_bridge_state_change(ftdm_channel_t
 			ftdm_channel_t *close_chan = ftdmchan;
 			sngss7_clear_ckt_flag(sngss7_info, FLAG_SUS_RECVD);
 			sngss7_clear_ckt_flag(sngss7_info, FLAG_T6_CANCELED);
+			sngss7_clear_ckt_flag (sngss7_info, FLAG_SENT_ACM);
+			sngss7_clear_ckt_flag (sngss7_info, FLAG_SENT_CPG);
+
 			sngss7_flush_queue(sngss7_info->event_queue);
 			sngss7_info->peer_data = NULL;
 			ftdm_channel_close (&close_chan);