MAVLink app: Fix sending of autopilot capabilities

src/modules/mavlink/mavlink_main.cpp

@@ -1620,7 +1620,10 @@ Mavlink::task_main(int argc, char *argv[])
 	/* now the instance is fully initialized and we can bump the instance count */
 	LL_APPEND(_mavlink_instances, this);
 
-	//send_autopilot_capabilites();
+	/* if the protocol is serial, we send the system version blindly */
+	if (get_protocol() != SERIAL) {
+		send_autopilot_capabilites();
+	}
 
 	while (!_task_should_exit) {
 		/* main loop */