The original default spec contain `seccomp` configuration,
but some OS do not support this feature, such as ubuntu14.04,
and `make test-cri` always fail. The containerd default spec dosen't
contain `seccomp`, so I think we could replace the default spec
with containerd default spec.
Signed-off-by: Yanqiang Miao <miao.yanqiang@zte.com.cn>