Fixed Python syntax error in staticfiles.serve

Syntax fix against:

    Traceback (most recent call last):
      File "./manage.py", line 10, in <module>
        execute_from_command_line(sys.argv)
      File "/home/jpic/dj15/src/django/django/core/management/__init__.py", line 399, in execute_from_command_line
        utility.execute()
      File "/home/jpic/dj15/src/django/django/core/management/__init__.py", line 392, in execute  
        self.fetch_command(subcommand).run_from_argv(self.argv)
      File "/home/jpic/dj15/src/django/django/core/management/__init__.py", line 272, in fetch_command
        klass = load_command_class(app_name, subcommand)
      File "/home/jpic/dj15/src/django/django/core/management/__init__.py", line 77, in load_command_class 
        module = import_module('%s.management.commands.%s' % (app_name, name))
      File "/home/jpic/dj15/src/django/django/utils/importlib.py", line 35, in import_module
        __import__(name)
      File "/home/jpic/dj15/src/django/django/contrib/staticfiles/management/commands/runserver.py", line 6, in <module>
        from django.contrib.staticfiles.handlers import StaticFilesHandler
      File "/home/jpic/dj15/src/django/django/contrib/staticfiles/handlers.py", line 13, in <module>
        from django.contrib.staticfiles.views import serve
      File "/home/jpic/dj15/src/django/django/contrib/staticfiles/views.py", line 20
        def serve(request, path insecure=False, **kwargs):
                                       ^
    SyntaxError: invalid syntax