Remove several unneeded modules from webkitpy.common.

Tools/Scripts/webkitpy/common/checksvnconfigfile.py

 # Copyright (C) 2012 Balazs Ankes (bank@inf.u-szeged.hu) University of Szeged
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1.  Redistributions of source code must retain the above copyright
 #     notice, this list of conditions and the following disclaimer.
 # 2.  Redistributions in binary form must reproduce the above copyright
 #     notice, this list of conditions and the following disclaimer in the
 #     documentation and/or other materials provided with the distribution.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # This file is used by:
-# webkitpy/tool/steps/addsvnmimetypeforpng.py
 # webkitpy/style/checkers/png.py
 
 import os
 import re
 
 
 def check(host, fs):
     """
     check the svn config file
     return with three logical value:
@@ skipping 20 matching lines @@
         config_file_path = fs.join(fs.expanduser("~"), ".subversion", "config")
     return config_file_path
 
 
 def errorstr_autoprop(config_file_path):
     return 'Have to enable auto props in the subversion config file (%s "enable-auto-props = yes"). ' % config_file_path
 
 
 def errorstr_png(config_file_path):
     return 'Have to set the svn:mime-type in the subversion config file (%s "*.png = svn:mime-type=image/png").' % config_file_path