iotests: Fix test outputs

iotests: Fix test outputs

039, 060 and 061 all create images with referenced clusters having a
refcount of 0. Because previous commits changed handling of such errors,
these tests now have a different output. Fix it.

Furthermore, 060 created a refblock with a refcount greater than one
which now results in having to rebuild the refcount structure as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>