For CNaaS machines we supply cloud-init user-data that does not create a
default user, in this case the script would exit half-way through. Now
it only tries to remove a user if it exists in the first place.
Now ubuntu also uses the updated way of preparing iaas instances like
debian did before, actually the debian scripts have been remade to also
handle ubuntu so we use a common code path.
Usage (what scripts to call) stay the same, but the underlying
operations takes less logins to complete.