fix up previous commit for stable

mercurial/extensions.py

@@ -24,7 +24,7 b' def find(name):'
 def load(ui, name, path):
     if name in _extensions:
         return
-    _extensions[shortname] = None
+    _extensions[name] = None
     if path:
         # the module will be loaded in sys.modules
         # choose an unique name so that it doesn't