Update yapf version

ports/devenv/devenv_small_test.py

 #!/usr/bin/env python
 # Copyright (c) 2014 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
-
 """Tests of the devenv app."""
 
 import os
 import sys
 
 SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.append(os.path.join(SCRIPT_DIR, '../..'))
 SRC_DIR = os.path.dirname(os.path.dirname(SCRIPT_DIR))
 TOOLCHAIN = os.environ.get('TOOLCHAIN', 'newlib')
 DEVENV_OUT_DIR = os.path.join(SRC_DIR, 'out/publish/devenv', TOOLCHAIN)
 
 import chrome_test
 
 
 app = os.path.join(DEVENV_OUT_DIR, 'app')
 test_dir = os.path.join(SCRIPT_DIR, 'tests')
 test_out_dir = os.path.join(DEVENV_OUT_DIR, 'tests')
 
 chrome_test.Main([
     '-C', test_dir,
     '-C', test_out_dir,
     '-t', '60',
     '--enable-nacl',
     '--load-extension', app,
     'devenv_small_test.html'] + sys.argv[1:])