[quadrapassel] Fix segmentation fault when down key was released after game was over

[Mario Wenzel <mariowenzel src gnome org>]

commit 2d2921442a9893a2a8c27e959138c71d0adc2c34
Author: Mario Wenzel <maweki gmail com>
Date:   Sat Jul 20 14:56:17 2013 +0200

    Fix segmentation fault when down key was released after game was over
    
    This bug is not caused by https://bugzilla.gnome.org/show_bug.cgi?id=704152

 src/game.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/game.vala b/src/game.vala
index 12d9ccc..bae8fed 100644
--- a/src/game.vala
+++ b/src/game.vala
@@ -372,7 +372,7 @@ public class Game : Object
 
     public void set_fast_forward (bool enable)
     {
-        if (fast_forward == enable)
+        if (fast_forward == enable || game_over)
             return;
         if (enable)
             if(!move_shape (0, 1, 0))