Backports from trunk:

- r1200955: Patch from Luke Meyer, clarifies usage of ProxyPassReverseCookiePath directive. As per bug #51126
- r1200968: A little clarification about variable interpolation, as requested in bug #51125
- r1202453: Fix xml


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1238730 13f79535-47bb-0310-9956-ffa450edef68