Added table entry placeholder for new header_parser callback

in all of the distributed modules.

Submitted by: Ken Coar, closes PR #191
Reviewed by: Roy Fielding, Chuck Murcko, Dean Gaudet, Marc Slemko, Jim Jagielski


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@77707 13f79535-47bb-0310-9956-ffa450edef68