refs #5638, make small changes to perf_child_txn.cc

git-svn-id: file:///svn/toku/tokudb@50880 c7de825b-a66e-492c-adef-691d508d4ae1

src/tests/perf_child_txn.cc

@@ -47,8 +47,10 @@ stress_table(DB_ENV* env, DB** dbp, struct cli_args *cli_args) {
 int
 test_main(int argc, char *const argv[]) {
     struct cli_args args = get_default_args_for_perf();
-    parse_stress_test_args(argc, argv, &args);
     args.single_txn = true;
+    parse_stress_test_args(argc, argv, &args);
+    args.num_elements = 0;
+    args.num_DBs = 0;
     stress_test_main(&args);
     return 0;
 }