Resolve "Could not find class" error when using android::addon

Hello! I think I have found (and fixed?) a bug in this module.

In my Puppet manifest:

```puppet
    android::addon {
        'addon-google_apis-google-17': ;
        'addon-google_apis-google-8':  ;
    }
```

I get the following error from Puppet:

```
Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Could not find class android::package for hostname on node hostname
```

Removing the include line in android::addon (it's not present in the similar android::platform) resolves this issue for me.