tests: Set print_category values explicitly

This will alow easily changing default values for print_category vs
print_category_hex later.

In any case, every test relying on logging output validation should
always explicitly state the config to avoid issues in the future if
default values change.

Related: OS#5034
Change-Id: If29b40557d5c2bcda04b964f344070bad58d8f28
diff --git a/tests/oap/oap_client_test.c b/tests/oap/oap_client_test.c
index dadf2ee..0ac32ea 100644
--- a/tests/oap/oap_client_test.c
+++ b/tests/oap/oap_client_test.c
@@ -261,6 +261,7 @@
 	log_set_use_color(osmo_stderr_target, 0);
 	log_set_print_timestamp(osmo_stderr_target, 0);
 	log_set_print_filename(osmo_stderr_target, 0);
+	log_set_print_category_hex(osmo_stderr_target, 0);
 	log_set_print_category(osmo_stderr_target, 1);
 	log_parse_category_mask(osmo_stderr_target, "DLOAP,1");