Backport mod_reqtimeout from trunk.

Reviewed by: sf, jorton, rjung

To take trawick's comment into account, I have changed enabled=yes into
enabled=most.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@917211 13f79535-47bb-0310-9956-ffa450edef68