Fixed #11532 -- Corrected the link used for edit_inline foreign keys in admin...

Fixed #11532 -- Corrected the link used for edit_inline foreign keys in admin when the admin is deployed using the old style admin.root approach. Thanks to JP for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11314 bcc190cf-cafb-0310-a4f2-bffc1f526a37