conn.salt contain "\0" not match the protocal specification 

http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeV10

defines the "string[8]      auth-plugin-data-part-1"

so if proxy.Conn.salt contains the "\0" character, some tools(sysbench, wireshark) can't parse the packet correctly.

![qq 20141205145418](https://cloud.githubusercontent.com/assets/1264866/5312147/eb94b3da-7c8e-11e4-92f7-bb70eb1b6a6a.jpg)