Somehow a 'do_dd must' had been commited. It was just a test, and
I can't even find in what commit it was added!
Just remove - not needed.
* Some test groups have been tagged as "This directory cannot be run on raw files".
  On Linux this is possible using loopback devices created by 'kpartx' (which
  simplifies the creation of all the partition mappings).
* Because most of the test groups config files assume a Illumos environment,
  we create a temporary, extra config file in the test groups 'setup.ksh' which
  is then included 'where needed'. This config file overwrites some of the
  values assumed in the test scripts with the correct /dev/mapper/loop[0-9]p[0-9]
  device paths.
* Since the designator for a slice in Illumos is 's' and in Linux 'p',
  it is instead replaced with a 'slice_part' variable which defaults to 's',
  but on Linux is set to 'p'. So something like '${disk}s${SLICE0}' is therefor
  replaced with '${disk}${slice_part}${SLICE0}' where needed.
* Because we use 'kpartx' and /dev/mapper devices, we can't call partition_cleanup()
  any more. This doesn't matter, because the test groups 'cleanup.ksh' and
  the tests cleanup() takes care of doing any updates of the device mappings
  for us.
* On Linux, the partitions start at 1, not 0 so take this into account when
  accessing slices/partitions.
On Linux the 'devices' keywoard is 'dev', and 'setuid' is 'suid'.