Fixed #8292 -- Honor filter_horizontal and filter_vertical in inlines...

Fixed #8292 -- Honor filter_horizontal and filter_vertical in inlines correctly. It now adds the right Javascript to handle them when they are the only ones on the page. Thanks dakrauth for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8392 bcc190cf-cafb-0310-a4f2-bffc1f526a37