mod_proxy_scgi: ProxySCGIInternalRedirect now allows an alternate

response header to be used by the application, for when the application
or framework is unable to return Location in the internal-redirect
form.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1674510 13f79535-47bb-0310-9956-ffa450edef68