Test fix

In reference to #17 

I'm not exactly sure whether it was a bug in the test, or with UI Router because I don't know this part of UI-Router very well.
The isset parameter now gets converted to a String. I checked it was a Boolean as of 0.2.11. This is why the test doesn't work anymore.

This one works:
```javascript
PermissionProvider.defineRole('withParams', function(params) {
  return params.isset === 'true';
});
```