Get rid of all the library tags.

lib/src/validator/pubspec.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 pub.validator.pubspec;
-
 import 'dart:async';
 
 import 'package:path/path.dart' as p;
 
 import '../entrypoint.dart';
 import '../validator.dart';
 
 /// Validates that a package's pubspec exists.
 ///
 /// In most cases this is clearly true, since pub can't run without a pubspec,
 /// but it's possible that the pubspec is gitignored.
 class PubspecValidator extends Validator {
   PubspecValidator(Entrypoint entrypoint)
       : super(entrypoint);
 
   Future validate() async {
     var files = entrypoint.root.listFiles(recursive: false, useGitIgnore: true);
     if (!files.any((file) => p.basename(file) == "pubspec.yaml")) {
       errors.add("The pubspec is hidden, probably by .gitignore.");
     }
   }
 }