Unknown license error when running `berks cookbook`

I can't get `berks cookbook` to work for me with Berkshelf v1.3.1, v1.4.4 or v2.0.1. I just get `Unknown license` errors:

```bash
berks cookbook --maintainer='Nordstrom, Inc.' --maintainer-email='me@example.com' nord_restaurant
      create  nord_restaurant/files/default
      create  nord_restaurant/templates/default
      create  nord_restaurant/attributes
      create  nord_restaurant/definitions
      create  nord_restaurant/libraries
      create  nord_restaurant/providers
      create  nord_restaurant/recipes
      create  nord_restaurant/resources
      create  nord_restaurant/recipes/default.rb
Unknown license: 'none'
```

```bash
berks cookbook --maintainer='Nordstrom, Inc.' --maintainer-email='me@example.com' --license=apache2 nord_restaurant
       create  nord_restaurant/files/default
       create  nord_restaurant/templates/default
       create  nord_restaurant/attributes
       create  nord_restaurant/definitions
       create  nord_restaurant/libraries
       create  nord_restaurant/providers
       create  nord_restaurant/recipes
       create  nord_restaurant/resources
Unknown license: 'apache2'
```