[1.0.X] Fixed #9494 -- Ensure the foreign key in an inline formset is always...

[1.0.X] Fixed #9494 -- Ensure the foreign key in an inline formset is always present on the forms. Thanks Fugazi for the report.

Backport of r9326 from trunk

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9327 bcc190cf-cafb-0310-a4f2-bffc1f526a37