Retire django-openstack-auth
``django_openstack_auth`` code was merged into the main horizon
repository during the queens release. This repo is already
deprecated and now we can retire it. This patch removes all
references of ``django_openstack_auth`` as mentioned in [1].
[1]
Needed-By:
- openstack/debtcollector
- openstack/dib-utils
- openstack/diskimage-builder
- - openstack/django_openstack_auth
- openstack/futurist
- openstack/glance
- openstack/glance_store
