fix: ensure we can deploy code when there is no pre or post-deploy script defined

Closes #3385

tests/apps/nodejs-express-noappjson/web.js

@@ -0,0 +1,12 @@
+var express = require('express');
+
+var app = express.createServer(express.logger());
+
+app.get('/', function(request, response) {
+  response.send('nodejs/express');
+});
+
+var port = process.env.PORT || 5000;
+app.listen(port, function() {
+  console.log("Listening on " + port);
+});