Save a few bytes in the conf pool.

The directive's names don't need to be duplicated in this pool when parsing the configuration file.

Either they match a known directive name and we can use it directly if needed. Otherwise, it is still possible to make a copy afterwards.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1744980 13f79535-47bb-0310-9956-ffa450edef68