Comment 7 for bug 1657305

I appreciate the need to move charms to the network-get --primary-address charm hook tool to support use of network spaces, but I still feel that there might be a 'undefined behaviour' use case in this code path.

If a user does not bind a relation or extra-binding, then what gets returned from network-get --primary-address <relation-name>? Does the unbound, default, behaviour mimic what unit-get private-address does?