Fix the SERVER_NAME variable under sub-request situations (where

`UseCanonicalName off' is used) like CGI's called from SSI pages or
RewriteCond variables by adopting r->hostname to sub-requests.

Submitted by: James Grinter <jrg@blodwen.demon.co.uk>
Reviewed by: Ralf S. Engelschall
PR: 3111


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82208 13f79535-47bb-0310-9956-ffa450edef68