fix application bug

vendor/github.com/miekg/dns/labels.go

@@ -28,9 +28,7 @@ func SplitDomainName(s string) (labels []string) {
 	case 1:
 		// no-op
 	default:
-		end := 0
-		for i := 1; i < len(idx); i++ {
-			end = idx[i]
+		for _, end := range idx[1:] {
 			labels = append(labels, s[begin:end-1])
 			begin = end
 		}