remove confusing flexibility for metadata interpretation

pkg/kubectl/cmd/cmd.go

@@ -21,6 +21,7 @@ import (
 	"io"
 	"os"
 
+	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apiserver/pkg/util/flag"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/kubernetes/pkg/kubectl/cmd/auth"
@@ -378,3 +379,5 @@ func deprecatedAlias(deprecatedVersion string, cmd *cobra.Command) *cobra.Comman
 	cmd.Hidden = true
 	return cmd
 }
+
+var metadataAccessor = meta.NewAccessor()