Add DirectoryIndex to fallback for resources

When DirectoryIndex is set FallbackResource disabled will do nothing because apache falls back to DirectoryIndex

Author: wimme002

setup/web_server_configuration.rst

@@ -127,6 +127,7 @@ and increase web server performance:
  # which will allow Apache to return a 404 error when files are
  # not found instead of passing the request to Symfony
  <Directory /var/www/project/public/bundles>
+ DirectoryIndex disabled
  FallbackResource disabled
  </Directory>
  ErrorLog /var/log/apache2/project_error.log