Rip out the last dart:io dependency from pkg/http.

pkg/http/test/io/http_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// 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 http_test;
+library http.test.io.http_test;
 
 import 'package:http/http.dart' as http;
 import 'package:unittest/unittest.dart';
 
 import 'utils.dart';
 
 main() {
   group('http.', () {
     tearDown(stopServer);
 
@@ skipping 309 matching lines @@
     });
 
     test('readBytes throws an error for a 4** status code', () {
       expect(startServer().then((_) {
         expect(http.readBytes(serverUrl.resolve('/error')),
             throwsClientException);
       }), completes);
     });
   });
 }