Fix mem leak in test.

test/test_graph.c

@@ -282,6 +282,8 @@ _graph_txn (LSUP_StoreType type)
     LSUP_graph_free (gr);
     if (type != LSUP_STORE_HTABLE) LSUP_store_free (store);
 
+    free_triples (trp); // gr copied data.
+
     return 0;
 }