Rename "pathos" package to "path".

pkg/barback/test/asset_test.dart

 // Copyright (c) 2013, 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 barback.test.asset_test;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:utf';
 
 import 'package:barback/barback.dart';
-import 'package:pathos/path.dart' as pathos;
+import 'package:path/path.dart' as pathos;
 import 'package:unittest/unittest.dart';
 
 import 'utils.dart';
 
 /// The contents of the test binary file.
 final binaryContents = [0, 1, 2, 3, 4];
 
 main() {
   initConfig();
 
@@ skipping 148 matching lines @@
     });
 
     group("file asset", () {
       test("shows the file path", () {
         var asset = new Asset.fromPath(id, "path.txt");
         expect(asset.toString(), equals('File "path.txt"'));
       });
     });
   });
 }