fix: force lsp to set from 0-0 INIT

Author: soonkuk

isaac/last_voteproofs.go

@@ -142,6 +142,13 @@ func (l *LastVoteproofsHandler) Set(vp base.Voteproof) bool {
 
 	lvps := l.last
 
+	if lvps.ivp == nil && lvps.avp == nil && lvps.mvp == nil {
+		initPoint := base.NewStagePoint(base.NewPoint(base.Height(0), base.Round(0)), base.StageINIT)
+		if vp.Point() != initPoint {
+			return false
+		}
+	}
+
 	if lvp := lvps.Cap(); lvp != nil {
 		lp, err := NewLastPointFromVoteproof(lvp)
 		if err != nil {