Merge r1026746 from trunk:

If an unknown Content-* header is received for a PUT request, we must not
ignore it but reply with 501 per RFC 2616 9.6.

PR: 42978

Submitted by: sf
Reviewed by: rpluem, covener, poirier


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1068310 13f79535-47bb-0310-9956-ffa450edef68