Prevent double warning when generating controllers

Before:

![screen shot 2014-09-21 at 12 52 10](https://cloud.githubusercontent.com/assets/34030/4348322/39b0a07c-4186-11e4-8fde-a9de9b9423ac.png)

After:

![screen shot 2014-09-21 at 12 52 36](https://cloud.githubusercontent.com/assets/34030/4348324/3e54a074-4186-11e4-80d3-52a445cc0805.png)