Simplify babel-state to just contain a seqno.
Simplify babel-state to just contain a seqno.

This is simpler and avoids issues with changing router-ids.

jech/babeld,Drooids/babeld,Gwendocg/babeldToS,Gwendocg/babeldToS,jech/babeld,tcatm/babeld,wlanslovenija/babeld,wlanslovenija/babeld