Fixed #10644: removed an undocumented, unused, and (as far as I can tell)...

Fixed #10644: removed an undocumented, unused, and (as far as I can tell) unnecessary "feature" of the ifchanged tag. Thanks, akaihola.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10438 bcc190cf-cafb-0310-a4f2-bffc1f526a37