containerd: disable cri plugin by default
It complains/fails if CNI is not available.
Also drop two obsolete keys.
state = "/run/containerd"
root = "/var/lib/containerd"
-snapshotter = "io.containerd.snapshotter.v1.overlayfs"
-differ = "io.containerd.differ.v1.base-diff"
+disabled_plugins = ["cri"]
[grpc]
address = "/run/containerd/containerd.sock"
