Error message is wrong when ssh fails

[ggiamarchi]

When ssh fails a message like the following is printed

SSH server unavailable on instance 1.2.3.4. You should maybe increase the timeout value which currently is 180 second(s).

The IP address referenced in the message is wrong because instead of printed the IP address we are trying to SSH into, it compute an available floating IP.

Here we must not call resolve_floating_ip method, we should reference the good IP instead. Furthermore, it's even a big mistake because the SSH IP is not necessarily a floating IP.

[ggiamarchi]

Should be resolved by #281