Remove DirectoryException and LinkException from dart:io and use FileException instaed.

tests/standalone/io/link_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "package:path/path.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
@@ skipping 186 matching lines @@
   testRename(base, file.path);
   testRename(base, dir.path);
 
   baseDir.deleteSync(recursive: true);
 }
 
 void testLinkErrorSync() {
   Expect.throws(() =>
       new Link('some-dir-that-doent exist/some link file/bla/fisk').createSync(
           'bla bla bla/b lalal/blfir/sdfred/es'),
-      (e) => e is LinkException);
+      (e) => e is FileSystemException);
 }
 
 checkExists(String filePath) => Expect.isTrue(new File(filePath).existsSync());
 
 testRelativeLinksSync() {
   Directory tempDirectory = Directory.systemTemp.createTempSync('dart_link');
   String temp = tempDirectory.path;
   String oldWorkingDirectory = Directory.current.path;
   // Make directories and files to test links.
   new Directory(join(temp, 'dir1', 'dir2')).createSync(recursive: true);
@@ skipping 20 matching lines @@
   tempDirectory.deleteSync(recursive: true);
 }
 
 main() {
   testCreateSync();
   testCreateLoopingLink();
   testRenameSync();
   testLinkErrorSync();
   testRelativeLinksSync();
 }