udf: Do not mark possibly inconsistent filesystems as closed

If logical volume integrity descriptor contains non-closed integrity
type when mounting the volume, there are high chances that the volume is
not consistent (device was detached before the filesystem was
unmounted). Don't touch integrity type of such volume so that fsck can
recognize it and check such filesystem.

Reported-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>