Get rid of all the library tags.

test/get/git/require_pubspec_test.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 pub_tests;
-
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration('requires the dependency to have a pubspec', () {
     ensureGit();
 
     d.git('foo.git', [
       d.libDir('foo')
     ]).create();
 
     d.appDir({"foo": {"git": "../foo.git"}}).create();
 
     pubGet(error: new RegExp(r'Could not find a file named "pubspec\.yaml" '
         r'in [^\n]\.'));
   });
 }