examples: fix mvc example to ignore files in controllers dir

fixes #3182

Author: dougwilson

examples/mvc/lib/boot.js

@@ -8,6 +8,7 @@ var fs = require('fs');
 module.exports = function(parent, options){
   var verbose = options.verbose;
   fs.readdirSync(__dirname + '/../controllers').forEach(function(name){
+    if (!fs.statSync(__dirname + '/../controllers/' + name).isDirectory()) return;
     verbose && console.log('\n   %s:', name);
     var obj = require('./../controllers/' + name);
     var name = obj.name || name;