Update MediaBrowser.Controller/Providers/DirectoryService.cs

Co-authored-by: Joe Rogers <1337joe@users.noreply.github.com>

MediaBrowser.Controller/Providers/DirectoryService.cs

@@ -3,7 +3,6 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using MediaBrowser.Model.IO;