dart:io | Tiny change to Link.exists().

sdk/lib/io/file_system_entity.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.
 
 part of dart.io;
 
 class FileSystemEntityType {
   static const FILE = const FileSystemEntityType._internal(0);
   static const DIRECTORY = const FileSystemEntityType._internal(1);
   static const LINK = const FileSystemEntityType._internal(2);
@@ skipping 35 matching lines @@
   static Future<int> _getTypeAsync(String path, bool followLinks) {
     // Get a new file service port for each request.  We could also cache one.
     var service = _FileUtils._newServicePort();
     List request = new List(3);
     request[0] = _TYPE_REQUEST;
     request[1] = path;
     request[2] = followLinks;
     return service.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionFromResponse(response,
-                                     "Error getting type of '$_path'");
+                                     "Error getting type of '$path'");
       }
       return response;
     });
   }
 
   /**
    * Do two paths refer to the same object in the file system?
    * Links are not identical to their targets, and two links
    * are not identical just because they point to identical targets.
    * Links in intermediate directories in the paths are followed, though.
@@ skipping 61 matching lines @@
       (_getTypeSync(path, true) == FileSystemEntityType.DIRECTORY._type);
 
   static _throwIfError(Object result, String msg) {
     if (result is OSError) {
       throw new FileIOException(msg, result);
     } else if (result is ArgumentError) {
       throw result;
     }
   }
 }