Fix warnings about `public` without arguments inside a method
Fix warnings about `public` without arguments inside a method

Some tests were doing this, and it has unexpected consequences so ruby
was throwing a warning like:

```
warning: calling public without arguments inside a method may not have the intended effect
```

activeadmin/inherited_resources,josevalim/inherited_resources,activeadmin/inherited_resources,josevalim/inherited_resources,activeadmin/inherited_resources,josevalim/inherited_resources