s/2.3/2.5/ and s/2.5/2.&httpd.minor;/ where applicable (assuming it works)

also note that a specific issue with mod_authn_dbd also applies to 2.4, so as to not confuse readers.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1387657 13f79535-47bb-0310-9956-ffa450edef68