net: deduplicate Socket.prototype.address

Signed-off-by: Fedor Indutny <fedor@indutny.com>

lib/net.js

@@ -340,13 +340,7 @@ Socket.prototype.setKeepAlive = function(setting, msecs) {
 
 
 Socket.prototype.address = function() {
-  if (this._handle && this._handle.getsockname) {
+  return this._getsockname();
-    var out = {};
-    var err = this._handle.getsockname(out);
-    // TODO(bnoordhuis) Check err and throw?
-    return out;
-  }
-  return null;
 };