Forbid selling units with unsalable cargo, permit selling military
Deities can customize which commodities can be sold in table item.
Default is to allow anything but civilians and military. However,
this applies only to the commodity market, not to the unit market:
cargo of ships and land units is not restricted.
Make the two markets consistent: permit selling military by default,
forbid selling units carrying unsalable commodities. This outlaws
selling units carrying civilians by default.