UEF drones upgrade removed

[Ithilis_Quo]

I found bug with drones, first one is very obvious, that its not posible be shoot down by air AA what is extremly big shit, but you probably know about that.

Second one is more complicate: When build drone upgrade and then another drone upgrade, and on drone setup "dont be rebuild after destroing". And this drone is destroed, then it remove both drone upgrades (not only one), when its destroing only one drone.