Adding a simple logging hook for mod_lua, which allows users to create their...

Adding a simple logging hook for mod_lua, which allows users to create their own logs or bypass the generic logging on a per-request basis.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1519277 13f79535-47bb-0310-9956-ffa450edef68