Remove iol_socket.h. This file had one declaration, and it makes more

sense for that declaraion to move to ap_iol.h.  This also modifies all of
the files that include iol_socket.h to include ap_iol.h


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85934 13f79535-47bb-0310-9956-ffa450edef68