Removed a bunch more Python 2.4 workarounds now that we don't support that...

Removed a bunch more Python 2.4 workarounds now that we don't support that version. Refs #15702 -- thanks to jonash for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15927 bcc190cf-cafb-0310-a4f2-bffc1f526a37