iotests: 222: Don't run with luks

Luks needs special parameters to operate the image. Since this test is
focusing on image fleecing, skip skip that format.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/222

@@ -25,6 +25,8 @@ import iotests
 from iotests import log, qemu_img, qemu_io, qemu_io_silent
 
 iotests.verify_platform(['linux'])
+iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk',
+                                            'vhdx', 'raw'])
 
 patterns = [("0x5d", "0",         "64k"),
             ("0xd5", "1M",        "64k"),