Fix a bug with inactive player unrent/sell settings

If the 'inactiveTimeUntilUnrent' or 'inactiveTimeUntilSell' settings
would be set to a value above 35000 it would cause an integer overflow,
resulting in a 50% chance that all regions will be unrentend/sold (and
if that does not happen it will still sell/unrent them too early). This
is caused by an integer overflow, switching to long fixed this problem.