Fixes an issue #128: `Response not working with lxml''. This error happend due to lxml's attempt to do .geturl() call on the response object. __getattr__ didn't raise AttributeError so response.geturl'' returned None and response.geturl()'' resulted into `TypeError: 'NoneType' object is not callable'' seen in the issue.

requests/models.py

@@ -416,7 +416,8 @@ class Response(object):
                 except zlib.error:
                     pass
             return self._content
-
+        else:
+            raise AttributeError
 
     def raise_for_status(self):
         """Raises stored :class:`HTTPError` or :class:`URLError`, if one occured."""