When the cgroup is removed, EventChan is closed (this was pulled in by
8d69c041c5). This results in a nil error
being received. Don't log an error in that case but instead return.
Signed-off-by: Jeremi Piotrowski <jpiotrowski@microsoft.com>
How to test (from https://github.com/opencontainers/runc/pull/2352#issuecomment-620834524):
(host)$ sudo swapoff -a
(host)$ sudo ctr run -t --rm --memory-limit $((1024*1024*32)) docker.io/library/alpine:latest foo
(container)$ sh -c 'VAR=$(seq 1 100000000)'
An event `/tasks/oom {"container_id":"foo"}` will be displayed in `ctr events`.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
