Remove unneeded check

ring/ring.go

@@ -727,7 +727,7 @@ func (r *Ring) ShuffleShard(identifier string, size int) ReadRing {
 // same identifier are with the same lookbackPeriod and increasing values of now.
 func (r *Ring) ShuffleShardWithLookback(identifier string, size int, lookbackPeriod time.Duration, now time.Time) ReadRing {
 	// Nothing to do if the shard size is not smaller than the actual ring.
-	if lookbackPeriod > 0 && (size <= 0 || r.InstancesCount() <= size) {
+	if size <= 0 || r.InstancesCount() <= size {
 		return r
 	}