Fix ap_directory_walk() per-dir merge bug seen when no <Directory /> is

present.

showstoppers--

Kudos to Jeff for finding it.
Kudos to BrianP for leading us in the right direction.
Kudos to OtherBill for pointing out the right way to fix this.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93425 13f79535-47bb-0310-9956-ffa450edef68