Prefs has become a heavy object with non-memcpy copy
semantics. We should not pass such a thing by value.
Signed-off-by: David Anderson <dave@natulte.net>
With this change, tailscaled can be restarted and reconnect
without interaction from `tailscale`, and `tailscale` is merely
there to provide login assistance and adjust preferences.
Signed-off-by: David Anderson <dave@natulte.net>