error if we can't detect containerd config version when patching containerd config

Author: BenTheElder

pkg/internal/patch/toml.go

@@ -40,6 +40,9 @@ func ContainerdTOML(toPatch string, patches []string, patches6902 []string) (str
 	if err != nil {
 		return "", errors.WithStack(err)
 	}
+	if version == 0 {
+		return "", errors.New("failed to detect containerd config version")
+	}
 	// apply merge patches
 	for _, patch := range patches {
 		pj, err := tomlToJSON([]byte(patch))