Add anti-entropy dir to cuttlefish schema

Got this warning when I started Riak w/ YZ enabled:

```
[warning] Config yokozuna/anti_entropy_data_dir is missing. Defaulting to: "./data/yz_anti_entropy"
```

But there is no setting (or default) in https://github.com/basho/yokozuna/blob/develop/priv/yokozuna.schema

cc/ @joedevivo