Code review comment for lp:~zhuzhaoyuan/mysql-proxy/zhuzhaoyuan

Rev 567 is fine with me, I'll merge that.

For rev 568 I would like to move the code into a network-mysqld-packet-lua.(hc) wrapper, like the other things we expose to make it reusable, instead of hardcoding it in the proxy plugin.
We also need to figure out which parts make sense to be mutable from Lua (max_packet_size is probably not a good candidate for being mutable, for instance).