message: camera: load definition from supplied URI
  We forgot to actually try to grab the camera definition file using the
  URI supplied via mavlink.
diff: @@ -879,6 +879,7 @@ void CameraImpl::process_camera_information(const mavlink_message_t &message)
  }
  } else {
  #endif
  + content = camera_information.cam_definition_uri;
  found_content = load_definition_file(camera_information.cam_definition_uri, content);
  #if !defined(WINDOWS)
  }
  