Merge r612954 from trunk:

* Do not try to read non existing response bodies of HEAD requests.

PR: 34275
Submitted by: Takashi Sato <serai lans-tv.com>
Reviewed by: rpluem

Submitted by: rpluem
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@649115 13f79535-47bb-0310-9956-ffa450edef68