Fix python scripts in src/tools/

tools/licenses.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.
 
 """Utility for checking and processing licensing information in third_party
 directories.
 
 Usage: licenses.py <command>
 
 Commands:
@@ skipping 217 matching lines @@
 
             # Don't recurse into any subdirs from here.
             dirs[:] = []
             continue
 
     for dir in ADDITIONAL_PATHS:
         third_party_dirs.append(dir)
 
     return third_party_dirs
 
+
 def ScanThirdPartyDirs():
     """Scan a list of directories and report on any problems we find."""
     third_party_dirs = FindThirdPartyDirs()
 
     errors = []
     for path in sorted(third_party_dirs):
         try:
             metadata = ParseDir(path)
         except LicenseError, e:
             errors.append((path, e.args[0]))
             continue
 
     for path, error in sorted(errors):
         print path + ": " + error
 
     return len(errors) == 0
 
+
 def GenerateCredits():
     """Generate about:credits, dumping the result to stdout."""
 
     def EvaluateTemplate(template, env, escape=True):
         """Expand a template with variables like {{foo}} using a
         dictionary of expansions."""
         for key, val in env.items():
             if escape:
                 val = cgi.escape(val)
             template = template.replace('{{%s}}' % key, val)
@@ skipping 17 matching lines @@
             'license': open(metadata['License File'], 'rb').read(),
         }
         entries.append(EvaluateTemplate(entry_template, env))
 
     file_template = open('chrome/browser/resources/about_credits.tmpl',
                          'rb').read()
     print "<!-- Generated by licenses.py; do not edit. -->"
     print EvaluateTemplate(file_template, {'entries': '\n'.join(entries)},
                            escape=False)
 
-if __name__ == '__main__':
+
+def main():
     command = 'help'
     if len(sys.argv) > 1:
         command = sys.argv[1]
 
     if command == 'scan':
         if not ScanThirdPartyDirs():
-            sys.exit(1)
+            return 1
     elif command == 'credits':
         if not GenerateCredits():
-            sys.exit(1)
+            return 1
     else:
         print __doc__
-        sys.exit(1)
+        return 1
+
+
+if __name__ == '__main__':
+  sys.exit(main())