Fixed #6322 -- Fixed bug in 'ifchanged' template tag where it wasn't resetting...

Fixed #6322 -- Fixed bug in 'ifchanged' template tag where it wasn't resetting itself properly in some cases. Thanks, nedbatchelder

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7752 bcc190cf-cafb-0310-a4f2-bffc1f526a37