mod_cgid: Don't allow Scriptsock to be specified inside VirtualHost;

Don't place script socket inside default server root instead of
actual server root.

The sock name was being stored in the server config, though it
was not specific to a server.

ap_server_root_relative() was being used prior to config processing,
so it was always picking up the default server root.

PR:            27886


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@103184 13f79535-47bb-0310-9956-ffa450edef68