When storing the response headers in mod_cache, omit Transfer-Encoding

and any other hop-by-hop headers that shouldn't be applied when the
response is later delivered from cache:
http://marc.theaimsgroup.com/?l=apache-httpd-dev&m=103727389213072
Diagnosed by: Estrade Matthieu <estrade-m@ifrance.com>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@97542 13f79535-47bb-0310-9956-ffa450edef68