Fix a typo in Dialog

sky/sdk/lib/widgets/dialog.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'basic.dart';
 import 'material.dart';
 
 class Dialog extends Component {
   Dialog({
     String key,
@@ skipping 15 matching lines @@
 
     List<Widget> children = new List<Widget>();
 
     if (title != null)
       children.add(title);
 
     if (content != null)
       children.add(content);
 
     if (actions != null)
-      children.add(content);
+      children.add(actions);
 
     return new Stack([
       new Listener(
         child: mask,
         onGestureTap: (_) => onDismiss()
       ),
       new Center(
         child: new ConstrainedBox(
           constraints: new BoxConstraints(minWidth: 280.0),
           child: new Material(
             level: 4,
             child: new ShrinkWrapWidth(
               child: new Block(children)
             )
           )
         )
       )
     ]);
   }
 }