Fixed a small bug

Author: Harshil Goel

worker/task.go

@@ -380,13 +380,12 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 	getMultiplePosting := q.DoCount || q.ExpandAll || listType || hasLang
 	//getMultiplePosting := true
 
-	cache := make([]*pb.PostingList, 0)
-
 	calculate := func(start, end int) error {
 		x.AssertTrue(start%width == 0)
 		out := &pb.Result{}
 		outputs[start/width] = out
 
+		cache := make([]*pb.PostingList, 0)
 		for i := start; i < end; i++ {
 			select {
 			case <-ctx.Done():