Remove unused variable.

git-svn-id: svn://localhost/ardour2/branches/3.0@7283 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/ardour/graph.h

@@ -88,7 +88,6 @@ class Graph : public SessionHandleRef
         std::list<Glib::Thread *> _thread_list;
         volatile bool _quit_threads;
         
-	node_list_t _nodes;
 	node_list_t _nodes_rt[2];
 
 	node_list_t _init_trigger_list[2];

libs/ardour/graph.cc

@@ -103,7 +103,6 @@ Graph::session_going_away()
         }
 
         // now drop all references on the nodes.
-        _nodes.clear();
         _nodes_rt[0].clear();
         _nodes_rt[1].clear();
         _init_trigger_list[0].clear();