add clip alias to correct place

keras_contrib/constraints/__init__.py

@@ -2,3 +2,7 @@ from __future__ import absolute_import
 from keras.constraints import *
 
 from .clip import Clip
+
+# Aliases.
+
+clip = Clip

keras_contrib/constraints/clip.py

@@ -19,7 +19,3 @@ class Clip(Constraint):
     def get_config(self):
         return {'name': self.__class__.__name__,
                 'c': self.c}
-
-# Aliases.
-
-clip = Clip