Code review comment for lp://staging/~freyes/maas-deployer/virtual-nodes

In general, I'm +1 on this. I feel that the virtual-nodes set is something that may be confusing rather than just nodes, however I do understand why its there (so there's a distinction of nodes to create and nodes which are expected to be present). I really waffled back and forth about whether to use virtual-nodes or to use a tag inside of a node, but ultimately it doesn't matter that much so I'll approve as is.