Fixed memory leak in LOD node.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@8020 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/graphics/lod_node.cpp

@@ -25,7 +25,11 @@ LODNode::LODNode(scene::ISceneNode* parent, scene::ISceneManager* mgr, s32 id)
 {
     assert(mgr != NULL);
     assert(parent != NULL);
-    parent->addChild(this);
+    // At this stage refcount is two: one because of the object being 
+    // created, and once because it is a child of the parent. Drop once,
+    // so that only the reference from the parent is active, causing this
+    // node to be deleted when it is removed from the parent.
+    drop();
 }
 
 LODNode::~LODNode()