Fixes shuttle ETA being given before arrive_time is set

Because the escape shuttle makes it's announcement inside an override of move(), arrive_time needs to be set before move() is called so that the correct ETA can be announced.

Having the announcement made inside /shuttle/ferry/emergency/move() seems kind of a bad way to do things, but the alternative is duplicating a lot of code inside the emergency shuttle's long_jump() proc. Still, that might be preferable to the way it is done now though.