Fixed crash when reading in old-style input files.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@6581 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/input/binding.cpp

@@ -55,7 +55,7 @@ bool Binding::deserialize(irr::io::IrrXMLReader* xml)
     // Convert strings to string tags to integer types
     m_type = (Input::InputType)atoi(event_string);
     m_id   = atoi(id_string);
-    m_character = atoi(character);
+    m_character = character ? atoi(character) : 0;
 
     // If the action is not a stick motion (button or key)
     if (m_type == Input::IT_STICKMOTION)