Stash the cgi PID earlier in mod_cgid

In some cases, a 2nd CGI using the same c->id can get into
the mod_cgid handler before cleanups have been run, causing
the new CGI pid to be used by the first CGI's cleanup function.

Instead of stashing c->id in the request processing thread,
just use it before leaving the handler to get the pid.

May indirectly fix PR57771, but it must have a slightly different
cause because stashing the conn_id slightly differently was 
supposed to be sufficient there.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1758083 13f79535-47bb-0310-9956-ffa450edef68