Making an install that used an existing RAID failed because of an
attempt to log the size of the RAID when rendering the curtin config.
This turns out to be because when the client sends the storage objects
back to the server it loses all the "api only" data including the udev
data that is needed to display the size.
In some sense this is a bit silly, we could just drop the log statement
and it would be fine but I think it's probably better to always have the
full storage objects in the server (until we can get away from this
hackish API anyway).
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