update restart function

MediaBrowser.Model/System/SystemInfo.cs

@@ -36,6 +36,8 @@ namespace MediaBrowser.Model.System
         /// <value><c>true</c> if this instance has pending restart; otherwise, <c>false</c>.</value>
         public bool HasPendingRestart { get; set; }
 
+        public bool IsShuttingDown { get; set; }
+
         /// <summary>
         /// Gets or sets a value indicating whether [supports library monitor].
         /// </summary>