THRIFT-4967: Node.js tutorial server fails if the zip function is invoked

Client: nodejs

This closes #1887.
diff --git a/tutorial/nodejs/NodeServer.js b/tutorial/nodejs/NodeServer.js
index 55d3817..2e19882 100644
--- a/tutorial/nodejs/NodeServer.js
+++ b/tutorial/nodejs/NodeServer.js
@@ -77,7 +77,6 @@
 
   zip: function() {
     console.log("zip()");
-    result(null);
   }
 
 });