rewrite_node_address_for_bridge() should set IPv6 preferences even if there is no ri
rewrite_node_address_for_bridge() should always set IPv6 preferences, even if there is only one of ri or rs. And it should always warn about them.
This goes back to commit c213f277 in 0.2.8.2-alpha and commit 9e9edf71 in 0.2.4.5-alpha.