Description:
1. start a container with restart=always.
`docker run -d --restart=always ubuntu sleep 3`
2. container init process exits.
3. use `docker pause <id>` to pause this container.

if the pause action is before cgroup data is removed and after the init process died.
`Pause` operation will success to write cgroup data, but actually do not freeze any process.

And then docker received pause event and stateExit event from
containerd, the docker state will be Running(paused), but the container
is free running.

Then we can not remove it, stop it , pause it and unpause it.

Signed-off-by: Wentao Zhang <zhangwentao234@huawei.com>