Removed unused attribute (#1117)

Signed-off-by: Alejandro Hernandez Cordero <[email protected]>

Author: ahcorde

image_proc/include/image_proc/track_marker.hpp

@@ -55,7 +55,6 @@ class TrackMarkerNode : public rclcpp::Node
 private:
   image_transport::CameraSubscriber sub_camera_;
 
-  int queue_size_;
   int marker_id_;
   double marker_size_;
   std::string image_topic_;