pkg/idtools: fix use of bufio.Scanner.Err

The Err() method should be called after the Scan() loop,
not inside it.

Fixes: 9a3ab0358ec
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

pkg/idtools/idtools.go

@@ -236,10 +236,6 @@ func parseSubidFile(path, username string) (ranges, error) {
 
 	s := bufio.NewScanner(subidFile)
 	for s.Scan() {
-		if err := s.Err(); err != nil {
-			return rangeList, err
-		}
-
 		text := strings.TrimSpace(s.Text())
 		if text == "" || strings.HasPrefix(text, "#") {
 			continue
@@ -260,5 +256,6 @@ func parseSubidFile(path, username string) (ranges, error) {
 			rangeList = append(rangeList, subIDRange{startid, length})
 		}
 	}
-	return rangeList, nil
+
+	return rangeList, s.Err()
 }