message: dronelink_impl: reject anything from sysid!=1
  There must still be some bug in the parsing of the mavlink messages
  which sometimes leads to messages with sysid different from 1.
  For now, let's work around this by just dropping those messages.
diff: @@ -49,6 +49,12 @@ void DroneLinkImpl::receive_message(const mavlink_message_t &message)
  return;
  }
  + // FIXME/TODO: reject anything which is not sysid 1
  + // somewhere there is a bug which produces.
  + if (message.sysid != 1) {
  + return;
  + }
  +
  create_device_if_not_existing(message.sysid, message.compid);
  remove_empty_devices();
  