Fix [hide_unit] on animationless unit moves

The was_hidden_ variable wasn't set in this particular codepath,
causing the unit to be unhidden at the end of the move.

src/unit_display.cpp

@@ -315,6 +315,7 @@ void unit_mover::proceed_to(unit& u, size_t path_index, bool update, bool wait)
 	// If no animation then hide unit until end of movement
 	if (!animate_)
 	{
+		was_hidden_ = u.get_hidden();
 		u.set_hidden(true);
 		return;
 	}