tests: consolidate scsi_debug usage

Signed-off-by: Karel Zak <kzak@redhat.com>
libblkid: arch independent minix detection

It seems that on-disk MINIX FS superblock is native-endian.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=833841
Signed-off-by: Karel Zak <kzak@redhat.com>
tests: add BE minix test

Signed-off-by: Karel Zak <kzak@redhat.com>