sfx mgr: Remove unused function declaration

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@13079 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/audio/sfx_manager.hpp

@@ -101,8 +101,6 @@ private:
 
     void                      loadSfx();
 
-    bool                      loadVorbisBuffer(const std::string &name,
-                                               ALuint buffer);
 public:
                              SFXManager();
     virtual                 ~SFXManager();