Fix a timing-out test.

test/must_pub_get_test.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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:pub/src/exit_codes.dart' as exit_codes;
 import 'package:pub/src/io.dart';
@@ skipping 251 matching lines @@
       });
 
       _requiresPubGet('The pubspec.lock file has changed since the .packages '
           'file was generated, please run "pub get" again.');
     });
 
     group("the lock file's SDK constraint doesn't match the current SDK", () {
       setUp(() {
         // Avoid using a path dependency because it triggers the full validation
         // logic. We want to be sure SDK-validation works without that logic.
-        servePackages((builder) {
+        globalPackageServer.add((builder) {
           builder.serve("foo", "3.0.0", pubspec: {
             "environment": {"sdk": ">=1.0.0 <2.0.0"}
           });
         });
 
         d.dir(appPath, [
           d.appPubspec({"foo": "3.0.0"})
         ]).create();
 
         pubGet(environment: {"_PUB_TEST_SDK_VERSION": "1.2.3+4"});
@@ skipping 129 matching lines @@
 void _touch(String path) {
   schedule(() async {
     // Delay a bit to make sure the modification times are noticeably different.
     // 1s seems to be the finest granularity that dart:io reports.
     await new Future.delayed(new Duration(seconds: 1));
 
     path = p.join(sandboxDir, "myapp", path);
     touch(path);
   }, "touching $path");
 }