Clean up the semantics of io.dart operations w.r.t. symlinks.

utils/tests/pub/install/git/lock_version_test.dart

 // Copyright (c) 2012, 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.
 
 library pub_tests;
 
 import 'dart:io';
 
 import '../../../../../pkg/pathos/lib/path.dart' as path;
 import '../../../../../pkg/scheduled_test/lib/scheduled_test.dart';
@@ skipping 17 matching lines @@
     schedulePub(args: ['install'],
         output: new RegExp(r"Dependencies installed!$"));
 
     d.dir(packagesPath, [
       d.dir('foo', [
         d.file('foo.dart', 'main() => "foo";')
       ])
     ]).validate();
 
     // Delete the packages path to simulate a new checkout of the application.
-    schedule(() => deleteDir(path.join(sandboxDir, packagesPath)));
+    schedule(() => deleteEntry(path.join(sandboxDir, packagesPath)));
 
     d.git('foo.git', [
       d.libDir('foo', 'foo 2'),
       d.libPubspec('foo', '1.0.0')
     ]).commit();
 
     // This install shouldn't update the foo.git dependency due to the lockfile.
     schedulePub(args: ['install'],
         output: new RegExp(r"Dependencies installed!$"));
 
     d.dir(packagesPath, [
       d.dir('foo', [
         d.file('foo.dart', 'main() => "foo";')
       ])
     ]).validate();
   });
 }