Get rid of all the library tags.

test/serve/gets_first_if_transitive_dependency_is_not_installed_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 'package:path/path.dart' as path;
 import 'package:pub/src/io.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
   integration("gets first if a transitive dependency is not installed", () {
@@ skipping 15 matching lines @@
 
     // Delete the system cache so bar isn't installed any more.
     schedule(() => deleteEntry(path.join(sandboxDir, cachePath)));
 
     pubGet();
     pubServe();
     requestShouldSucceed("packages/bar/bar.dart", 'main() => "bar 1.2.3";');
     endPubServe();
   });
 }