If we get "container not found" error from containerd, it's possibly because that this container has already been stopped. It will be ok to ignore this error and just return an empty stats. Signed-off-by: Yuanhong Peng <pengyuanhong@huawei.com> Upstream-commit: 4a6cbf9bcb78d38c48ef963f585f0fadf733e101 Component: engine