mod_disk_cache: If the Vary'd content is stale, we can handle it via our

freshness tests which will attempt to revalidate the content.

* modules/cache/mod_disk_cache.c
  (open_entity): If the root Vary index is stale, we don't need to throw away
  potentially stale content - we can try to refresh it.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@539054 13f79535-47bb-0310-9956-ffa450edef68