Skinny: don't hangup remote calls

src/mod/endpoints/mod_skinny/skinny_server.c

@@ -1268,7 +1268,9 @@ switch_status_t skinny_handle_on_hook_message(listener_t *listener, skinny_messa
 
 		channel = switch_core_session_get_channel(session);
 
-		switch_channel_hangup(channel, SWITCH_CAUSE_NORMAL_CLEARING);
+		if (skinny_line_get_state(listener, line_instance, call_id) != SKINNY_IN_USE_REMOTELY) {
+			switch_channel_hangup(channel, SWITCH_CAUSE_NORMAL_CLEARING);
+		}
 	}
 
 	if(session) {