Merge r1753257 from trunk:

Restore 'HEAD' method as a special case of GET with the common ID
Submitted by: wrowe
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1757672 13f79535-47bb-0310-9956-ffa450edef68