failed to create a security group with firewall-mode: none

[Martin Packman]

Setting firewall-mode to 'none' and bootstrapping on an openstack deployment that does not support security groups fails trying to create the global group.

This is an issue for deploying on rackspace's openstack using juju:

<https://lists.ubuntu.com/archives/juju/2015-June/005396.html>

Generally we do want to at least try creating a group and using it to ensure we have ssh access, but need to either detect and accept the lack of the os-security-groups extension or just log and continue when getting a 404 if the firewall-mode is none.

The global group is also always created on ec2, but as that cloud always supports security groups it's less of an issue.