Minor fixes for IPAVersion class
Py3: classes with __eq__ must provide __hash__ function or set __hash__
to None.
Comparison function like __eq__ must signal unsupported types by
returning NotImplemented. Python turns this in a proper TypeError.
Make the version member read-only and cache _bytes represention.
https://fedorahosted.org/freeipa/ticket/6473
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Martin Basti <mbasti@redhat.com>