removal double assignements

utils/exporters/blender/addons/io_three/constants.py

@@ -251,8 +251,6 @@ CAST_SHADOW = 'castShadow'
 RECEIVE_SHADOW = 'receiveShadow'
 QUAD = 'quad'
 
-USER_DATA = 'userData'
-
 MASK = {
     QUAD: 0,
     MATERIALS: 1,