removed extra lock

MediaBrowser.Controller/Entities/Folder.cs

@@ -765,8 +765,6 @@ namespace MediaBrowser.Controller.Entities
                     var innerProgress = new ActionableProgress<double>();
 
                     innerProgress.RegisterAction(p =>
-                    {
-                        lock (progress)
                     {
                         percentages.TryUpdate(child.Id, p / 100, percentages[child.Id]);
 
@@ -774,7 +772,6 @@ namespace MediaBrowser.Controller.Entities
                         percent /= list.Count;
 
                         progress.Report((90 * percent) + 10);
-                        }
                     });
 
                     await ((Folder)child).ValidateChildren(innerProgress, cancellationToken, recursive: recursive).ConfigureAwait(false);