mod_cgid: Terminate CGI scripts when the client connection

drops.

This is done by mod_cgid daemon remembering the pid, which is queried
by the handler at the end of the request.  The handler then
knocks out the CGI script (if it is indeed still running).

It would be slightly easier for the daemon to do this, but naughty
scripts which are hard to kill would hold up all new CGI requests
if the daemon stopped its normal processing to kill a script.

PR:		8388


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@97489 13f79535-47bb-0310-9956-ffa450edef68