crtools: Add --file-locks option

Add --file-locks/-l option to support handling file locks, for safety,
only used for container.

Originally-signed-off-by: Zheng Gu <cengku.gu@huawei.com>
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>