Enable the spec of testing crash of protocol module.

spec/static/main.js

@@ -133,7 +133,7 @@ app.on('ready', function() {
   app.setApplicationMenu(menu);
 
   // Test if using protocol module would crash.
-  // require('protocol').registerProtocol('test-if-crashes', function() {});
+  require('protocol').registerProtocol('test-if-crashes', function() {});
 
   window = new BrowserWindow({
     title: 'atom-shell tests',