Fix a couple bugs introduced in the last CL.

lib/src/unparsed_frame.dart

 // Copyright (c) 2015, 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 stack_trace.unparsed_frame;
 
 import 'frame.dart';
 
 /// A frame that failed to parse.
 ///
 /// The [member] property contains the original frame's contents.
 class UnparsedFrame implements Frame {
   final Uri uri = new Uri(path: "unparsed");
   final int line = null;
   final int column = null;
   final bool isCore = false;
   final String library = "unparsed";
   final String package = null;
   final String location = "unparsed";
 
   final String member;
 
   UnparsedFrame(this.member);
 
-  String toString() => _original;
+  String toString() => member;
 }