Make critical error logs more understandable.
Make critical error logs more understandable.

TBR=tyoshino@chromium.org, bashi@chromium.org

Review URL: https://codereview.appspot.com/6298070

git-svn-id: a751b5b3dcfba0ee4592a85c40d2fdd063ca0d53@639 4ff78f4a-9131-11de-b045-6380ec9940d4

XiaonuoGantan/pywebsocket,XiaonuoGantan/pywebsocket