Largely reduce the number of pylint warnings and fix one typo.

gclient_scm.py

 # Copyright (c) 2010 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.
 
 """Gclient-specific SCM-specific operations."""
 
 import logging
 import os
 import posixpath
 import re
-import sys
 import time
 
 import scm
 import gclient_utils
 
 
 class DiffFilterer(object):
   """Simple class which tracks which file is being diffed and
   replaces instances of its file name in the original and
   working copy lines of the svn/git diff output."""
@@ skipping 905 matching lines @@
 
     This method returns a new list to be used as a command."""
     new_command = command[:]
     if revision:
       new_command.extend(['--revision', str(revision).strip()])
     # --force was added to 'svn update' in svn 1.5.
     if ((options.force or options.manually_grab_svn_rev) and
         scm.SVN.AssertVersion("1.5")[0]):
       new_command.append('--force')
     return new_command