Backport trunk revisions 1209432 and 1233604:

SECURITY: CVE-2011-4317 (cve.mitre.org)
Resolve additional cases of URL rewriting with ProxyPassMatch or
RewriteRule, where particular request-URIs could result in undesired
backend network exposure in some configurations.

Submitted by: jorton
Reviewed by: trawick, covener, gregames


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1235443 13f79535-47bb-0310-9956-ffa450edef68