django.utils.functional is missing update_wrapper import

[ijstokes]

Changeset 15927 for django/trunk/django/utils/functional.py contains:

from functools import wraps

but I think it should contain:

from functools import wraps, update_wrapper

At least "grappelli" requires "update_wrapper", so in my local copy I've added it in.

[Jannis Leidel]

In [15965]:

Fixed #15724 -- Added update_wrapper import to utils.functional to be a bit more forgiving for 3rd party apps using that import.