Merge r1830746 from trunk:

mod_proxy_html: Fix variable interpolation and memory allocation failure in ProxyHTMLURLMap.

Proposed by: Ewald Dieterich <ewald mailbox.org>
Reviewed by: ylavic


Submitted by: ylavic
Reviewed by: ylavic, jailletc36, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1833840 13f79535-47bb-0310-9956-ffa450edef68