ipn, wgengine: plumb NetworkMap down to magicsock

Now we can have magicsock make decisions based on tailcfg.Debug
settings sent by the server.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/local.go

@@ -230,6 +230,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		if changed {
 			b.updateFilter(st.NetMap)
 			b.updateDNSMap(st.NetMap)
+			b.e.SetNetworkMap(st.NetMap)
 		}
 		if disableDERP {
 			b.e.SetDERPMap(nil)