Remove ap_lingering_close from all of the MPMs. This is now done as

Remove ap_lingering_close from all of the MPMs. This is now done as
a cleanup registered with the connection_pool.  I have also turned
ap_lingering_close into a static function, because it is only used
in connection.c.  This is the next step to consolidating all of the
socket function calls.  ap_lingering_close will only be added if the
core is dealing with a standard socket.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91832 13f79535-47bb-0310-9956-ffa450edef68