Fixed #16241 -- Ensured the WSGI iterable's close() is always called.

        super(ServerHandler, self).error_output(environ, start_response)

        return ['\n'.join(traceback.format_exception(*sys.exc_info()))]

    # Backport of http://hg.python.org/cpython/rev/d5af1b235dab. See #16241.

    # This can be removed when support for Python <= 2.7.3 is deprecated.

    def finish_response(self):

        try:

            if not self.result_is_file() or not self.sendfile():

                for data in self.result:

                    self.write(data)

                self.finish_content()

        finally:

            self.close()

class WSGIServer(simple_server.WSGIServer, object):

    """BaseHTTPServer that implements the Python WSGI protocol"""