Fix python scripts in src/tools/

tools/unused-symbols-report.py

-#!/usr/bin/python
-# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+#!/usr/bin/env python
+# Copyright (c) 2011 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.
 
-"""Print a report of symbols stripped by the linker due to being unused.
+"""Prints a report of symbols stripped by the linker due to being unused.
 
 To use, build with these linker flags:
   -Wl,--gc-sections
   -Wl,--print-gc-sections
 the first one is the default in Release; search build/common.gypi for it
 and to see where to add the other.
 
 Then build, saving the output into a file:
   make chrome 2>&1 | tee buildlog
 and run this script on it:
@@ skipping 142 matching lines @@
 
   if len(args) < 1:
     parser.print_help()
     sys.exit(1)
 
   iter = Parse(open(args[0]),
                skip_paths=opts.skip_paths,
                only_paths=opts.only_paths)
   Output(iter)
 
+
 if __name__ == '__main__':
   main()