Worked around method_decorator problem with custom getattr

This addresses the fact that django's method_decorator does not cope
with argumented (or instantitated at all) decorators.

This can and should be removed if upstream changes make it possible to
do so.

References:

The python bug (fixed in 3.3+ only, not backporting) http://bugs.python.org/issue3445
django cache_page fix: https://code.djangoproject.com/ticket/13093
django handling missing attributes: https://github.com/django/django/blob/c3aa2948c6c14862407501290571f858ccf45b07/django/utils/decorators.py#L73
django bugs: https://code.djangoproject.com/ticket/21513, https://code.djangoproject.com/ticket/13879
Merge pull request #1820 from dpwrussell/decorator_fix

Worked around method_decorator problem with custom getattr