Fix File to Close

Signed-off-by: hang.jiang <hang.jiang@daocloud.io>

libcontainer/cgroups/fs/paths.go

@@ -83,6 +83,7 @@ func tryDefaultCgroupRoot() string {
 	if err != nil {
 		return ""
 	}
+	defer dir.Close()
 	names, err := dir.Readdirnames(1)
 	if err != nil {
 		return ""

update.go

@@ -182,6 +182,7 @@ other options are ignored.
 				if err != nil {
 					return err
 				}
+				defer f.Close()
 			}
 			err = json.NewDecoder(f).Decode(&r)
 			if err != nil {