Fixed #12428: Ensured that the dummy backend is installed correctly on a fresh...

Fixed #12428: Ensured that the dummy backend is installed correctly on a fresh project generated by django-admin.py startproject. Thanks to Simon for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11974 bcc190cf-cafb-0310-a4f2-bffc1f526a37