Fixed #5943 -- Modified django-admin to behave like manage.py if settings are...

Fixed #5943 -- Modified django-admin to behave like manage.py if settings are provided, either as --settings or DJANGO_SETTINGS_MODULE. Thanks to Joseph Kocherhans and Todd O'Bryan for their work on this ticket.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8282 bcc190cf-cafb-0310-a4f2-bffc1f526a37