Update vendor directory

Re-added cobra patch 499475bb41

vendor/google.golang.org/appengine/namespace.go

@@ -8,41 +8,18 @@ import (
 	"fmt"
 	"regexp"
 
-	"github.com/golang/protobuf/proto"
+	"golang.org/x/net/context"
 
 	"google.golang.org/appengine/internal"
-	basepb "google.golang.org/appengine/internal/base"
 )
 
 // Namespace returns a replacement context that operates within the given namespace.
-func Namespace(c Context, namespace string) (Context, error) {
+func Namespace(c context.Context, namespace string) (context.Context, error) {
 	if !validNamespace.MatchString(namespace) {
 		return nil, fmt.Errorf("appengine: namespace %q does not match /%s/", namespace, validNamespace)
 	}
-	return &namespacedContext{
-		Context:   c,
-		namespace: namespace,
-	}, nil
+	return internal.NamespacedContext(c, namespace), nil
 }
 
 // validNamespace matches valid namespace names.
 var validNamespace = regexp.MustCompile(`^[0-9A-Za-z._-]{0,100}$`)
-
-// namespacedContext wraps a Context to support namespaces.
-type namespacedContext struct {
-	Context
-	namespace string
-}
-
-func (n *namespacedContext) Call(service, method string, in, out proto.Message, opts *internal.CallOptions) error {
-	// Apply any namespace mods.
-	if mod, ok := internal.NamespaceMods[service]; ok {
-		mod(in, n.namespace)
-	}
-	if service == "__go__" && method == "GetNamespace" {
-		out.(*basepb.StringProto).Value = proto.String(n.namespace)
-		return nil
-	}
-
-	return n.Context.Call(service, method, in, out, opts)
-}