[1.7] Collective Farm Fix
Some fixes for collectivized agriculture.
In the vanilla game, when adopting collectivized agriculture land laws, it would cause miscalculations of subsistence farm buildings, e.g., a plantation was built but the original subsistence farm would not downgrade or disappear, leaving the subsistence farms standing forever; some errors accumulated and even caused some plots to have thousands of empty subsistence farms.
This was fixed by adjusting the cap on worker-owned agricultural buildings, so that local labor now defaults to holding 80% of the shares instead of 100%, allowing subsistence farms to downgrade properly.
