[Apple DOS filesystem] Fix file sizes.

Aaru.Filesystems/AppleDOS/File.cs

@@ -337,8 +337,12 @@ public sealed partial class AppleDOS
         if(_extentCache.ContainsKey(filename))
             _extentCache.Remove(filename);
 
+        if(_fileSizeCache.ContainsKey(filename))
+            _fileSizeCache.Remove(filename);
+
         _fileCache.Add(filename, fileMs.ToArray());
         _extentCache.Add(filename, tsListMs.ToArray());
+        _fileSizeCache.Add(filename, (int)fileMs.Length);
 
         return ErrorNumber.NoError;
     }