changes to tzinfo break Zope's DateTime

Recipe for reproducing failure:

  $ svn co http://svn.zope.org/repos/main/DateTime/trunk
  ...
  $ vim setup.py # remove pin of 'pytz <= 2010b', leaving just 'pytz'
  $ /path/to/python bootstrap.py
  ...
  $ bin/buildout
  ...
  $ bin/test --all

which yields a ton of failures.

I've flagged this as wontfix as Zope2 has worked around the issue. I don't like that the API change was not backwards compatible though, so we can revisit if other people are having problems. I suspect the problem is too late to fix now though, as people will be relying on the new behavior.