freetdm: fix REL receiving leg always stay in TERMINATING stae in

         native bridge mode
         - This is supposed to be included in commit of
           b324f867. Somehow it's
           not included in that commit. Without this change, the
           REL receiving leg always stay in TERMINATING state when
           received an incoming REL message.

libs/freetdm/src/ftdm_io.c

@@ -2199,9 +2199,12 @@ static ftdm_status_t _ftdm_channel_call_hangup_nl(const char *file, const char *
 {
 	ftdm_status_t status = FTDM_SUCCESS;
 
-	if (ftdm_test_flag(chan, FTDM_CHANNEL_NATIVE_SIGBRIDGE)) {
+	/* In native sigbridge mode we ignore hangup requests from the user and hangup only when the signaling module decides it */
+	if (ftdm_test_flag(chan, FTDM_CHANNEL_NATIVE_SIGBRIDGE) && chan->state != FTDM_CHANNEL_STATE_TERMINATING) {
+
 		ftdm_log_chan_ex(chan, file, func, line, FTDM_LOG_LEVEL_DEBUG, 
 				"Ignoring hangup in channel in state %s (native bridge enabled)\n", ftdm_channel_state2str(chan->state));
+		ftdm_set_flag(chan, FTDM_CHANNEL_USER_HANGUP);
 		goto done;
 	}