Documentation: should use '--floating_ip' option for OpenStack

[rdefauw]

When using kargo to create a cluster on OpenStack, I am running kargo on my own workstation. If I don't use the '--floating_ip' option when running 'kargo openstack ...' then the process fails when trying to check connectivity to the newly created VMs as it tries to use the IP addresses from the private network.

The documentation should include a note on this. (I actually wonder if it's ever useful to not use this option; using the private IP addresses would only work if you are running kargo from a machine on the same private network.)

[Smana]

Thanks for reporting, ok i'll add a word about this option.