Bugfix (pressing F10 when no game is running could crash).

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@7048 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/input/input_manager.cpp

@@ -199,7 +199,7 @@ void InputManager::handleStaticAction(int key, int value)
             // Fall through to put the game into pause mode.
 #endif
         case KEY_F10:
-            history->Save();
+            if(world) history->Save();
             break;
         default:
             break;