Merge r1734412 from trunk:

mod_authz_host: add a new "forward-dns" authorization type

This new type does not rely on reverse DNS lookups.

Submitted by: fabien
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1735947 13f79535-47bb-0310-9956-ffa450edef68