Cause dav_fs_get_parent_resource to fail if the file path is entirely
  invalid or incomplete, or if it is root [determined by the platform's
  apr implemention].  Identified by Greg Stein.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92998 13f79535-47bb-0310-9956-ffa450edef68