Merge r1751930 from trunk:

mention mod_cgid too

http://httpd.apache.org/docs/2.4/howto/cgi.html#comment_5623



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1751932 13f79535-47bb-0310-9956-ffa450edef68