Use "package:" imports for pub.

test/cache/repair/reinstalls_git_packages_test.dart

 // 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 pub_tests;
 
 import 'package:path/path.dart' as path;
+import 'package:pub/src/io.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../../lib/src/io.dart';
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration('reinstalls previously cached git packages', () {
     // Create two cached revisions of foo.
     d.git('foo.git', [
       d.libDir('foo'),
       d.libPubspec('foo', '1.0.0')
@@ skipping 38 matching lines @@
           d.dir("lib", [d.file("foo.dart", 'main() => "foo";')])
         ]);
       }).toList();
 
       d.dir(cachePath, [
         d.dir("git", fooLibs)
       ]).validate();
     });
   });
 }