fix 640,change create way is same as java client

[baomingyu]

Fixes #640

Master Issue: #640

go client create producer and consumer client way is different with java client. and go client will throw error when call grabCnx while Lookup or after sending CommandProducer. if use get this error, use must retry recreate client and this way is not neccessary. and connect need to reconnect while send or connect check way.

java client handle like this, so it need be changed .

and java code is this