When returning 401 response, WebSocketRequestHandler.parse_request must return False

Returning False prevents the default handler from being run

R=ricea@chromium.org

Review URL: https://codereview.appspot.com/138370043

git-svn-id: http://pywebsocket.googlecode.com/svn/trunk@849 4ff78f4a-9131-11de-b045-6380ec9940d4