Since prefork is currently the only non-threaded MPM, check for it, instead of...

Since prefork is currently the only non-threaded MPM, check for it, instead of testing for each threaded MPM type.  This enables mod_cgid on the Event MPM by default, which is a "Good Thing"(tm).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@156572 13f79535-47bb-0310-9956-ffa450edef68