fixes for running on devices with protetion information

[Christoph Hellwig <hch@lst.de>]

Hi all,

currently various tests either hang or fail when running on devices
with protection information.  This series makes tests using
unsupported device mapper targets _notrun instead of hanging or
failing with obscure errors.

Bote that to usefully run on devices with PI you'll also need my kernel
patches that fix a regression in PI information stacking and the
one-liner to add dm-error support for passing on integrity data.

Diffstat:
 common/dmthin     |   10 +++++-----
 tests/generic/081 |    3 ++-
 tests/generic/459 |    6 ++++--
 3 files changed, 11 insertions(+), 8 deletions(-)