Delete a bunch of packages that are now on GitHub.

pkg/oauth2/lib/src/authorization_exception.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 authorization_exception;
-
-/// An exception raised when OAuth2 authorization fails.
-class AuthorizationException implements Exception {
-  /// The name of the error. Possible names are enumerated in [the spec][].
-  ///
-  /// [the spec]: http://tools.ietf.org/html/draft-ietf-oauth-v2-31#section-5.2
-  final String error;
-
-  /// The description of the error, provided by the server. Defaults to null.
-  final String description;
-
-  /// A URI for a page that describes the error in more detail, provided by the
-  /// server. Defaults to null.
-  final Uri uri;
-
-  /// Creates an AuthorizationException.
-  AuthorizationException(this.error, this.description, this.uri);
-
-  /// Provides a string description of the AuthorizationException.
-  String toString() {
-    var header = 'OAuth authorization error ($error)';
-    if (description != null) {
-      header = '$header: $description';
-    } else if (uri != null) {
-      header = '$header: $uri';
-    }
-    return '$header.';
-  }
-}