Fix python scripts in src/tools/

tools/swig/swig.py

-#!/usr/bin/python
+#!/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.
 
 """Wrapper around swig.
 
 Sets the SWIG_LIB environment var to point to Lib dir
 and defers control to the platform-specific swig binary.
 
 Depends on swig binaries being available at ../../third_party/swig.
@@ skipping 20 matching lines @@
   platform_flags = {
       'darwin': '-DSWIGMAC',
       'linux2': '-DSWIGLINUX',
       'linux3': '-DSWIGLINUX',
       'win32':  '-DSWIGWIN',
   }
   swig_bin = os.path.join(swig_dir, dir_map[sys.platform], 'swig')
   args = [swig_bin, platform_flags[sys.platform]] + sys.argv[1:]
   args = [x.replace('/', os.sep) for x in args]
   print "Executing", args
-  sys.exit(subprocess.call(args))
+  return subprocess.call(args)
 
 
 if __name__ == "__main__":
-  main()
-
+  sys.exit(main())