storage: succeed in DeleteContainer if container is unknown
storage: succeed in DeleteContainer if container is unknown

Signed-off-by: Peter Hunt <fb7b1ad57b81f1e149129d77ecccc59c02fe0648@redhat.com>

kubernetes-incubator/ocid,kubernetes-incubator/ocid,nalind/cri-o,nalind/cri-o,nalind/cri-o,kubernetes-incubator/ocid