Improve the performance and reliability of redis store.

similar issue : #1133

- Improve the performance of subscribe/unsubscribe/message event logic. (redis.js)
- Remove duplicates clearHandlers call. (transport.js)

I operate the system which have lots of simultaneous connections. (frequent reconnection)
As time passed, The performance and reliability drops dramatically.

I applied the changed code and the performance and reliability was dramatically improved.

If it was helpful to the other person, it will be good.