Move setup_listeners to listen.c. This renames it to ap_setup_listeners,

and removes the duplicated code from all effected MPMs.  The only this
doesn't touch, is Windows.  That MPM was using a different setup_listeners.
If one of the Windows guys would like to modify the WinNT MPM to use the
same setup_lsiteners, that would be VERY cool.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85809 13f79535-47bb-0310-9956-ffa450edef68