Fix load, unload, lload, lunload not to give away civilians

Fix load, unload, lload, lunload not to give away civilians

The game generally doesn't let you give away civilians.  But the check
in load_comm_ok() for that compared the sector old owner to the player
instead of the ship's or land unit's owner, which is incorrect for
foreign ships or land units.  Fix that.

Also make fix the message there not to assume that the civilians are
owned by the player.  This can't currently happen, but will when these
commands support use by deities properly.