common/atomicwrites: fix _require_scratch_write_atomic

common/atomicwrites: fix _require_scratch_write_atomic

Fix this function to call _notrun whenever something fails.  If we can't
figure out the atomic write geometry, then we haven't satisfied the
preconditions for the test.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>