Reauth flow generates duplicate devices

[dcmeglio]

As reported on #12 if you go through a reauth workflow, duplicate devices are created instead of updating the existing ones.

[cquinlan]

Can confirm the same behavior. I have a stack of about 10 duplicate devices I have to prune when I complete the re-auth.

[dcmeglio]

I plan to try to figure this out this weekend. That said, the main cause of the reauth has been fixed so this really shouldn't occur very frequently.