encapsulate path substitution

MediaBrowser.Controller/Entities/BaseItem.cs

@@ -2111,10 +2111,7 @@ namespace MediaBrowser.Controller.Entities
         {
             if (locationType == LocationType.FileSystem || locationType == LocationType.Offline)
             {
-                foreach (var map in ConfigurationManager.Configuration.PathSubstitutions)
-                {
-                    path = LibraryManager.SubstitutePath(path, map.From, map.To);
-                }
+                return LibraryManager.GetPathAfterNetworkSubstitution(path);
             }
 
             return path;

MediaBrowser.Controller/Library/ILibraryManager.cs

@@ -506,6 +506,8 @@ namespace MediaBrowser.Controller.Library
         /// <returns>QueryResult&lt;BaseItem&gt;.</returns>
         QueryResult<BaseItem> QueryItems(InternalItemsQuery query);
 
+        string GetPathAfterNetworkSubstitution(string path);
+
         /// <summary>
         /// Substitutes the path.
         /// </summary>