Current implementation of this API always returns
checks output of 'crictl pods -q' and filters out everything
that doesn't start with k8s_. 'crictl pods -q' returns only pod ids,
so everything is always filtered out.
Removing filtering by name prefix should fix this.
Fixes: kubernetes/kubeadm#926
This API return error when underlying 'inspect' command
fails. This makes ImagePullCheck to fail as it doesn't expect
runtime.ImageExists to return an error even if image doesn't exist.
Fixed this by returning error nil even when inspect command fails.
