When sending a proxy request of the form

When sending a proxy request of the form
  GET http://[3ffe:1:1001:3000:230:5ff:fe05:3c3c]/server-status HTTP/1.0
through the httpd-2.x mod_proxy.c code, while a directive
  ProxyDomain .my.dom.ain
is in effect, the request is redirected to
  Location: http://[3ffe:1:1001:3000:230:5ff:fe05:3c3c.my.dom.ain]/server-status

The patch fixes this bug, by testing whether the hostname part of the
unparsed_uri contains colon characters (which is the case only for
IPv6 literals).

This patch is also a candidate for httpd-2.0 and httpd-2.2

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@632304 13f79535-47bb-0310-9956-ffa450edef68