Remove hardcoded buildComplete delay in some overlays

There certainly was and possibly still is some issue this was trying to
work around, but unless it's a deal-breaker, we should rather try to fix that
issue directly instead of keeping some uncommented magical work-around.

OpenRA.Mods.D2k/Traits/Render/WithDeliveryOverlay.cs

@@ -71,8 +71,7 @@ namespace OpenRA.Mods.D2k.Traits.Render
 
 		void INotifyBuildComplete.BuildingComplete(Actor self)
 		{
-			self.World.AddFrameEndTask(w => w.Add(new DelayedAction(120, () =>
-				buildComplete = true)));
+			buildComplete = true;
 		}
 
 		void INotifySold.Sold(Actor self) { }