It was broken by efaa7c4e when it dropped the device name "image"
from BB API.  Now this error message text is updated again, sync it up.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-id: 20170119130759.28319-3-famz@redhat.com
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>