HELLO response with node missing IP address

In our testing environment, we saw a Disque node start to respond to `HELLO` with a response missing an IP address for its own node (it had neither 127.0.0.1 nor the local network IP - two interfaces available on this machine):

```
127.0.0.1:7711> hello
1) (integer) 1
2) "e4b6ad92530fa59da330ff921d9ef00ed1eea985"
3) 1) "e4b6ad92530fa59da330ff921d9ef00ed1eea985"
2) ""
3) "7711"
4) "1"
```

This confused the client I was using to no end. The client shouldn't try to use the HELLO information for a cluster of one node, but it was trying to anyway, and not expecting the missing IP.

Uptime on this disque node was 7 days, with very low load over that time.