Normalize packages' library names.

This makes the library names play nicer with dartdoc.

Review URL: https://codereview.chromium.org//13674024

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@21106 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/lib/src/client.dart b/lib/src/client.dart
index afb59e4..0d422af 100644
--- a/lib/src/client.dart
+++ b/lib/src/client.dart
@@ -2,7 +2,7 @@
 // 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 client;
+library oauth2_client;
 
 import 'dart:async';
 import 'dart:uri';