logging_vty: Fix segfault un unused entries in log_info_cat array of app
diff --git a/src/vty/logging_vty.c b/src/vty/logging_vty.c
index fc1ca43..a6d2f52 100644
--- a/src/vty/logging_vty.c
+++ b/src/vty/logging_vty.c
@@ -632,6 +632,10 @@
 		const struct log_category *cat = &tgt->categories[i];
 		char cat_lower[32];
 
+		/* skip empty entries in the array */
+		if (!osmo_log_info->cat[i].name)
+			continue;
+
 		/* stupid old osmo logging API uses uppercase strings... */
 		osmo_str2lower(cat_lower, osmo_log_info->cat[i].name+1);
 		osmo_str2lower(level_lower, log_level_str(cat->loglevel));