message: core: correctly retrying after receiving unsupported.
diff: @@ -487,6 +487,7 @@ void SystemImpl::send_autopilot_version_request()
  if (fut.get() == MavlinkCommandSender::Result::Unsupported) {
  _old_message_520_supported = false;
  LogWarn() << "Trying alternative command (512).";
  + send_autopilot_version_request();
  }
  }
  @@ -514,6 +515,7 @@ void SystemImpl::send_flight_information_request()
  if (fut.get() == MavlinkCommandSender::Result::Unsupported) {
  _old_message_528_supported = false;
  LogWarn() << "Trying alternative command (512)..";
  + send_flight_information_request();
  }
  }
  