fix [DEP0005] DeprecationWarning

Buffer() is deprecated due to security and usability issues.
It is suggested to use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.


Also discussed in spdy-http2#5

lib/deceiver.js

@@ -247,7 +247,7 @@ Deceiver.prototype.emitBody = function emitBody (buffer) {
 
 Deceiver.prototype._emitEmpty = function _emitEmpty () {
   // Emit data to force out handling of UPGRADE
-  var empty = new Buffer(0)
+  var empty = Buffer.alloc ? Buffer.alloc(0) : new Buffer(0)
   if (this.socket.ondata) { this.socket.ondata(empty, 0, 0) } else {
     this.socket.emit('data', empty)
   }