core: Use process scoreboard to store each child's listener bucket,

and silently adjust the configured number of processes/threads to
be above the computed number of listener buckets (depending on the
CPU cores).



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1629909 13f79535-47bb-0310-9956-ffa450edef68