Comment # 4 on bug 964365 from Josef Reidinger

OK, problem is loop device which have partition where device key is empty and
code do not expect it:

/dev/loop: $["device":"/dev/loop", "name":"loop",
"partitions":[$["create_file":false, "detected_fs":`iso9660, "device":"",

Checking code this part of code is no longer used with dropping of
perl-bootloader usage.

Robert - can you please retest it with Leap42.2 beta? and if it occurs can you
please attach fresh logs?

Thanks