Ejecting from a scoped fork of react-scripts doesn't work

Created by: gaearon

Even after https://github.com/facebookincubator/create-react-app/issues/1706 fixes it, ejecting still won't work because the package will be one folder deeper.

We should fix our folder resolution to understand scoped packages.

As we fix this we should also remember to test the npm link integration in case it breaks.