Fix import order with isort tool.

tools/telemetry/telemetry/value/failure_unittest.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.
 
 import os
 import sys
+import traceback
 import unittest
-import traceback
 
 from telemetry import value
 from telemetry.page import page_set
 from telemetry.value import failure
 
+
 class TestBase(unittest.TestCase):
   def setUp(self):
     self.page_set = page_set.PageSet(file_path=os.path.dirname(__file__))
     self.page_set.AddPageWithDefaultRunNavigate("http://www.bar.com/")
 
   @property
   def pages(self):
     return self.page_set.pages
 
 class ValueTest(TestBase):
@@ skipping 28 matching lines @@
     d = {
       'type': 'failure',
       'name': exc_info[0].__name__,
       'units': '',
       'value': ''.join(traceback.format_exception(*exc_info))
     }
     v = value.Value.FromDict(d, {})
 
     self.assertTrue(isinstance(v, failure.FailureValue))
     self.assertEquals(v.name, 'Exception')