Fix all errors related to apreq in doxygen processing.

Remove useless comment. As far as I have tested (with dox 1.8.6), it works as described in doxygen doc.

Generated docs are still only visible from the "List File". More work is needed to have them included within the "Module/Core routine" architecture. However they are now useable and the ouput of "make dox" is now readable :)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1611480 13f79535-47bb-0310-9956-ffa450edef68