[libgda] test-ddl: replace removed _free() API from DDL

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 370353093e79228be9dadebeb78f89c87cf8ab63
Author: Daniel Espinosa <esodan gmail com>
Date:   Sat Sep 8 17:55:44 2018 -0500

    test-ddl: replace removed _free() API from DDL

 tests/ddl/check-ddl-base.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/tests/ddl/check-ddl-base.c b/tests/ddl/check-ddl-base.c
index 188c5dd58..178b7d36f 100644
--- a/tests/ddl/check-ddl-base.c
+++ b/tests/ddl/check-ddl-base.c
@@ -42,7 +42,8 @@ static void
 test_ddl_base_finish (BaseFixture *self,
                      gconstpointer user_data)
 {
-       gda_ddl_base_free (self->obj);
+       if (self->obj)
+               g_object_unref (self->obj);
 }
 
 static void