boe.actions.cpp: correct a mistake when using arrows to move target

Scenario Editor: some cleaning + reset the terrain center correctly if it is
  outside the terrain bounds...

src/scenedit/scen.graphics.hpp

@@ -37,5 +37,4 @@ bool is_road(short i,short j);
 short string_length(char *str);
 rectangle get_custom_rect (short which_rect);
 void init_dialogs();
-void record_display_strings();
 sf::Vector2f translate_mouse_coordinates(sf::Vector2i const point);