Fix import order with isort tool.

tools/telemetry/telemetry/core/browser_credentials_unittest.py

 # Copyright 2012 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 tempfile
 import unittest
 
 from telemetry.core import browser_credentials
 
+
 SIMPLE_CREDENTIALS_STRING = """
 {
   "google": {
     "username": "example",
     "password": "asdf"
   }
 }
 """
 
 class BackendStub(object):
@@ skipping 42 matching lines @@
       self.assertEqual("example",
                        google_backend.login_needed_called[1]["username"])
       self.assertEqual("asdf",
                        google_backend.login_needed_called[1]["password"])
 
       browser_cred.LoginNoLongerNeeded(tab, 'google')
       self.assertTrue(google_backend.login_no_longer_needed_called is not None)
       self.assertEqual(tab, google_backend.login_no_longer_needed_called[0])
     finally:
       os.remove(f.name)