Floating ip address updates

Fixes: https://bugs.launchpad.net/bugs/1364419

This is the second attempt to fix this issue. The first PR added code to use the floating IP address but it turns out that was only called at bootstrap, and then later the address poller overwrote the addresses. So extra code was needed in the instance gathering to also update the floating address details.
I checked and sadly ServerDetail.AddressIPv4 etc is not filled in. I noticed according to the Openstack docs we had left off a json tag, but even updating that it still came back empty. I suspect that it might be an extension that isn't universally enabled.

I've fixed AllInstances()