wgengine/router.CallbackRouter needs to support both the Router
and OSConfigurator interfaces, so the setters can't both be called
Set.
Signed-off-by: David Anderson <danderson@tailscale.com>
It's only use to skip some optional initialization during cleanup,
but that work is very minor anyway, and about to change drastically.
Signed-off-by: David Anderson <danderson@tailscale.com>
It's currently unused, and no longer makes sense with the upcoming
DNS infrastructure. Keep it in tailcfg for now, since we need protocol
compat for a bit longer.
Signed-off-by: David Anderson <danderson@tailscale.com>
