The option --list might not be available on older versions, the
equvalent is --all. Discovered via failed travis build.
Signed-off-by: David Sterba <dsterba@suse.com>
The current user might not be able to peek into the loop files directly,
use the helper. Discovered by running tests in travis.
Signed-off-by: David Sterba <dsterba@suse.com>