Update perf page_set to use story_set

tools/perf/page_sets/intl_es_fr_pt-BR.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+from telemetry import story
 from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
 from telemetry.page import shared_page_state
 
 
 class IntlEsFrPtBrPage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(IntlEsFrPtBrPage, self).__init__(
         url=url, page_set=page_set,
         shared_page_state_class=shared_page_state.SharedDesktopPageState)
     self.archive_data_file = 'data/intl_es_fr_pt-BR.json'
 
 
-class IntlEsFrPtBrPageSet(page_set_module.PageSet):
+class IntlEsFrPtBrPageSet(story.StorySet):
 
   """
   Popular pages in Romance languages Spanish, French and Brazilian Portuguese.
   """
 
   def __init__(self):
     super(IntlEsFrPtBrPageSet, self).__init__(
       archive_data_file='data/intl_es_fr_pt-BR.json',
-      bucket=page_set_module.PARTNER_BUCKET)
+      cloud_storage_bucket=story.PARTNER_BUCKET)
 
     urls_list = [
       'http://elmundo.es/',
       'http://terra.es/',
       # pylint: disable=C0301
       'http://www.ebay.es/sch/i.html?_sacat=382&_trkparms=clkid%3D6548971389060485883&_qi=RTM1381637',
       'http://www.eltiempo.es/talavera-de-la-reina.html',
       'http://www.free.fr/adsl/index.html',
       'http://www.voila.fr/',
       'http://www.leboncoin.fr/annonces/offres/limousin/',
       'http://www.orange.fr/',
       # Why: #5 site in Brazil
       'http://www.uol.com.br/',
       # Why: #10 site in Brazil
       # pylint: disable=C0301
       'http://produto.mercadolivre.com.br/MLB-468424957-pelicula-protetora-smartphone-h5500-e-h5300-43-frete-free-_JM'
     ]
 
     for url in urls_list:
       self.AddUserStory(IntlEsFrPtBrPage(url, self))