Small hotfix - amending the issue with dispatching vehicles

Some of the players reported an issue where the vehicle dispatch would stop working for them, after the game's been left running for a longer while.

This was due to the dispatch script trying to find unit that should no longer actually be there (dead or otherwise gone from the map). Fixed now.

I will also push the fog of war update soon, but at first - I will only release it the test branches - I'm afraid it might still need some more testing, before it's safe to deliver it to the general public.