riak.conf update needed

[macintux]

At least, I hope one is.

http://docs.basho.com/riak/2.0.0beta1/ops/advanced/install-custom-code/

Still refers to add_paths via app.config

[macintux]

Upon further review, I'm guessing it just needs to refer to advanced.config

[lucperkins]

I'm closing this issue for now, as it is covered in #1161