update debug_test with logging system changes

Thanks to Konrad Meier
diff --git a/openbsc/tests/debug/debug_test.c b/openbsc/tests/debug/debug_test.c
index 6800021..fb5ce7a 100644
--- a/openbsc/tests/debug/debug_test.c
+++ b/openbsc/tests/debug/debug_test.c
@@ -25,7 +25,7 @@
 {
 	struct log_target *stderr_target;
 
-	log_init(&log_info);
+	log_init(&log_info, NULL);
 	stderr_target = log_target_create_stderr();
 	log_add_target(stderr_target);
 	log_set_all_filter(stderr_target, 1);