OK
Fired when a model is unregistered, typically when the server
is killed. Useful for tearing-down remaining open connections,
etc.

@param  {Function} cb [description]
@return {[type]}      [description]
 Teardown a Connection OK
function (conn, cb) {
            if (LOG_DEBUG) {
                console.log("BEGIN tearDown");
            }
            
            if (typeof conn == 'function') {
                cb = conn;
                conn = null;
            }
            if (!conn) {
                connections = {};
                return cb();
            }
            if (!connections[conn])
                return cb();
            delete connections[conn];
            cb();
        }