Try to live with cruel reality fact - if_vmove doesn't move an
interface from previous vnet cloning infrastructure to the new
one. Let's admit this as design feature and make it work better.
- Delete two blocks of code that would fallback to vnet0, if a cloner isn't found. They didn't do any good job and also whole idea of treating vnet0 as special one is wrong.
- When deleting a cloned interface, lookup its cloner using it's home vnet.
With this change simple sequence works correctly:
ifconfig foo0 create jail -c name=jj persist vnet vnet.interface=foo0 jexec jj ifconfig foo0 destroy