Directly use ParentId

MediaBrowser.Controller/Providers/ItemInfo.cs

@@ -11,7 +11,7 @@ namespace MediaBrowser.Controller.Providers
         public ItemInfo(BaseItem item)
         {
             Path = item.Path;
-            ParentId = item.GetParent().Id;
+            ParentId = item.ParentId;
             IndexNumber = item.IndexNumber;
             ContainingFolderPath = item.ContainingFolderPath;
             IsInMixedFolder = item.IsInMixedFolder;