Use `except ... as ...:` syntax to improve compatibility with Python3.
|Reported by:||Alex Ogier||Owned by:||nobody|
|Has patch:||yes||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
We are dropping python 2.5 support in django 1.5, so the old style with commas is no longer needed. This should make the diff with the Py3 guys much smaller.
Also a pull request, https://github.com/django/django/pull/134