radix: fix a memleak when removing the last node

src/util-radix-tree.c

@@ -1194,7 +1194,7 @@ static void SCRadixRemoveKey(uint8_t *key_stream, uint16_t key_bitlen,
     /* we are deleting the root of the tree.  This would be the only node left
      * in the tree */
     if (tree->head == node) {
-        SCFree(node);
+        SCRadixReleaseNode(node, tree);
         tree->head = NULL;
         SCRadixReleasePrefix(prefix, tree);
         return;