Prefer /dev/disk/by-id/scsi-[A-Z] over /dev/disk/by-id/scsi-1*

The latter seems to be Type1 SCSI compatibility links, which
do not always exist on SLE11 SP3 due to udev bugs.
Merge pull request #154 from dirkmueller/release/pebbles/master

Prefer /dev/disk/by-id/scsi-[A-Z] over /dev/disk/by-id/scsi-1*