Add logging to CloudCafe. Fix Horizon IP retrieval.

Left out the logging module before. Also fixed a function call to be an attribute instead so that CloudCafe testing can work.
A while ago, I changed `horizon_ip` to be a property of the deployment, so I think `self.deployment.horizon_ip` returns a str and `self.deployment.horizon_ip()` would try to invoke the string. 

See [here](https://github.com/rcbops-qa/monster/blob/master/monster/deployments/rpcs/deployment.py#L143)