Allow packet struct to contain more than #xffffff octets.
Allow packet struct to contain more than #xffffff octets.

The my-packet-stream structure doesn't just represent a MySQL protocol
packet, it also has a payload that may expand more than a single
packet (see 5.1.2.1 Big packets).

That fixes https://github.com/dimitri/pgloader/issues/247 for me.

qitab/qmynd,dkochmanski/qmynd