Use pub_server package

pkg/pub_server/lib/shelf_pubserver.dart

 // Copyright (c) 2014, 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 pubserver.shelf_pubserver;
+library pub_server.shelf_pubserver;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:logging/logging.dart';
 import 'package:mime/mime.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:shelf/shelf.dart' as shelf;
 import 'package:yaml/yaml.dart';
 
@@ skipping 376 matching lines @@
 
   Uri _uploadSimpleUrl(Uri url) {
     return url.resolve('/api/packages/versions/newUpload');
   }
 
   Uri _finishUploadSimpleUrl(Uri url, {String error}) {
     var postfix = error == null ? '' : '?error=${Uri.encodeComponent(error)}';
     return url.resolve('/api/packages/versions/newUploadFinish$postfix');
   }
 }