(ARM-16) Remove :permissions => [] as valid scenario

With it being more possible that someone might have a bug in a hiera script
than to reasonably want ACLs locked down to nobody having permission,
we decided to change the support for this to what a reasonable person might
expect if they had a bug in their scripts that would cause :permissions => [].

This will cause Puppet to error and not attempt to move forward with setting
the permissions in a surprising way.