Comment 4 for bug 1476779

Seems, we cannot do anything while node is being added or its roles are being changed. AFAIC, we should not forbid the change of nodes' set or roles' set for node if they are not in costistency with the current template. And do not reset the current template either. We could just raise an error when serialization of template is requested or introduce some flag that will show is the current template in consistency with the environment's configuration.
The second thing to do is to check the template itself for its consistency while it is being loaded.