Port over some fixes to mod_dav 1.0 so that the Apache 2.0 DAV code

will pass the "litmus" DAV test tool.

In particular, we need to properly handle empty namespaces properly.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94482 13f79535-47bb-0310-9956-ffa450edef68