Sync the 'http-dynamic-prop-namespaces' branch with recent trunk changes. (Merged /subversion/trunk:r1398942-1398962.) git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/http-dynamic-prop-namespaces@1398963 13f79535-47bb-0310-9956-ffa450edef68