Bugfix in admin forms using PermissionInline as inlines.

Hello,

This is basically the same fix as suggested by the following pull-request on bitbucket:

https://bitbucket.org/jezdez/django-authority/pull-request/1/bugfix-in-admin-forms-using

by Ratnadeep Debnath

It really is an issue because the modeladmins which want to use the inline are rendered useless this way.

I hope this fix can be incorporated and released to pypi soon.

Thank you very much in advance,

Best regards,

Rico