consensus: check current chain height before processing timer

The chain may already be more current than our dBFT state (like when the node
has commited something at view 0, but all the other nodes changed view and
accepted something at view 1), so in this case we should reinit dBFT on new
height.

pkg/consensus/consensus.go

@@ -168,7 +168,14 @@ func (s *service) eventLoop() {
 			s.log.Debug("timer fired",
 				zap.Uint32("height", hv.Height),
 				zap.Uint("view", uint(hv.View)))
+			if s.Chain.BlockHeight() >= s.dbft.BlockIndex {
+				s.log.Debug("chain already advanced",
+					zap.Uint32("dbft index", s.dbft.BlockIndex),
+					zap.Uint32("chain index", s.Chain.BlockHeight()))
+				s.dbft.InitializeConsensus(0)
+			} else {
 				s.dbft.OnTimeout(hv)
+			}
 		case msg := <-s.messages:
 			fields := []zap.Field{
 				zap.Uint16("from", msg.validatorIndex),