store user-provided data in PlaneTracker class

samples/python2/plane_tracker.py

@@ -77,7 +77,7 @@ class PlaneTracker:
                 descs.append(desc)
         descs = np.uint8(descs)
         self.matcher.add([descs])
-        target = PlanarTarget(image = image, rect=rect, keypoints = points, descrs=descs, data=None)
+        target = PlanarTarget(image = image, rect=rect, keypoints = points, descrs=descs, data=data)
         self.targets.append(target)
 
     def clear(self):