Fix compilation warning in python-wy.el after lexical rewrite

* admin/grammars/python.wy: Require semantic/tag.

In end of data:
cedet/semantic/wisent/python-wy.el:862:1: Warning: the function
    `semantic-tag-name' might not be defined at runtime.

admin/grammars/python.wy

@@ -91,6 +91,7 @@
 %expectedconflicts 5
 
 %{
+(require 'semantic/tag)
 (declare-function wisent-python-reconstitute-function-tag
 		  "semantic/wisent/python" (tag suite))
 (declare-function wisent-python-reconstitute-class-tag "semantic/wisent/python"