This is a fix that went into v1.3 quite a while back, but not into v2.0.

It sorts out the problem when a password protected reverse proxy URL
sends a Proxy-Authenticate to a browser instead of a WWW-Authenticate.

This patch covers the changes to the httpd-2.0 tree.

Submitted by:	Graham Leggett
Reviewed by:	Chuck Murcko


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88527 13f79535-47bb-0310-9956-ffa450edef68