Check for no timezone in dateformat.py

[Claude Paroz]

The DateFormat class in source:django/trunk/django/utils/dateformat.py has a self.timezone attribute that can be None (self.timezone = getattr(dt, 'tzinfo', None)). However, it is not checked for None value when called in I(), T(), U() and Z() methods.

This can lead to AttributeError:

File "/usr/lib/python2.5/site-packages/django/utils/dateformat.py", line 195, in T
    name = self.timezone.tzname(self.data)

AttributeError: 'NoneType' object has no attribute 'tzname'

[Malcolm Tredinnick]

(In [9919]) Fixed #10048 -- Handle non-existent timezone in dateformat functions.

[Malcolm Tredinnick]

(In [9920]) [1.0.X] Fixed #10048 -- Handle non-existent timezone in dateformat functions.

Backport of r9919 from trunk.

[Jacob]

Milestone 1.1 deleted