Fixed #16873 - Added dummy database backend in default settings, so that just importing django.db doesn't trigger ImproperlyConfigured if there is no DATABASES setting.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16946 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/conf/global_settings.py

@@ -143,6 +143,9 @@ SEND_BROKEN_LINK_EMAILS = False
 
 # Database connection info.
 DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.dummy',
+    },
 }
 
 # Classes used to implement db routing behaviour