Make rtssh set public Cuttlefish IPs for PB/HTTP

Something in Riak has changed such that the previous approach to setting public IPs no longer appears to work for `rtssh`. Thus, `rtssh` users such as [rtcloud](https://github.com/basho/rtcloud) cannot provision clusters that can talk on anything other than `127.0.0.1`.

This commits add code that explicitly sets the PB/HTTP IPs when Cuttlefish is being used, which seems to fix the issue.

***Note:*** This change uses hardcoded ports for the new PB/HTTP settings, and thus only works if there's a single Riak instance per node. Since [rtcloud](https://github.com/basho/rtcloud) is the only real consumer of `rtssh` currently and `rtcloud` currently runs 1 Riak instance per node, this is fine for now. We should consider changing in the future when we're not in a release crunch.