parser schema CHANGE always return non-const modules

Refs #1645
diff --git a/tests/utests/data/test_validation.c b/tests/utests/data/test_validation.c
index 2045a3a..643655c 100644
--- a/tests/utests/data/test_validation.c
+++ b/tests/utests/data/test_validation.c
@@ -737,7 +737,7 @@
 test_defaults(void **state)
 {
     struct lyd_node *tree, *node, *diff;
-    const struct lys_module *mod;
+    struct lys_module *mod;
     const char *schema =
             "module f {\n"
             "    namespace urn:tests:f;\n"