Fixed deprecation warning in kron.py.

theano/sandbox/linalg/kron.py

 from theano import tensor
 from theano.tensor.slinalg import kron
 
-def deprecation_warning():
-    # Make sure the warning is displayed only once.
-    if deprecation_warning.already_displayed:
-        return
-
-    warnings.warn(
+warnings.warn(
         "theano modules are deprecated and will be removed in release 0.7",
         stacklevel=3)
-    deprecation_warning.already_displayed = True
+deprecation_warning.already_displayed = True
\ No newline at end of file