Fix the previous fix

Lib/lib2to3/refactor.py

@@ -174,7 +174,7 @@ class RefactoringTool(object):
         """
         fixer_pkg = self.fixer_dir.replace(os.path.sep, ".")
         if os.path.altsep:
-            fixer_pkg = self.fixer_dir.replace(os.path.altsep, ".")
+            fixer_pkg = fixer_pkg.replace(os.path.altsep, ".")
         pre_order_fixers = []
         post_order_fixers = []
         fix_names = self.options.fix