net: support Server.listen(Pipe)

lib/net.js

@@ -972,6 +972,7 @@ Server.prototype._listen = function() {
   var backlog = toNumber(arguments[1]) || toNumber(arguments[2]);
 
   var TCP = process.binding('tcp_wrap').TCP;
+  var Pipe = process.binding('pipe_wrap').Pipe;
 
   if (arguments.length == 0 || typeof arguments[0] == 'function') {
     // Bind to a random port.
@@ -984,7 +985,7 @@ Server.prototype._listen = function() {
     } else if (h.handle) {
       h = h.handle;
     }
-    if (h instanceof TCP) {
+    if (h instanceof TCP || h instanceof Pipe) {
       self._handle = h;
       listen(self, null, -1, -1, backlog);
     } else if (typeof h.fd === 'number' && h.fd >= 0) {