The unit activation check compared the last vehicle's index where it
meant the time the unit left it, so it could report a false "unit
activation logic error" just after a vehicle exit. Messages only.
The actors.c line only; the commit's other fix, the movement point's y
printed as z, came with "Log and error messages print what their formats
ask for".
(cherry picked from commit e3089220a6bfa8479ba2e334a0070f97c97dd851)
Milenko
42cfa397f7