restore the SO_REUSEADDR for listening sockets; it is absolutely

required on most (all?) platforms, regardless of what code changes
might be required to work around the ability on Windows to
inadvertently have more than one server listening on the same ports


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93252 13f79535-47bb-0310-9956-ffa450edef68