Don't free if it's NULL

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2154 65c4cc65-6c06-0410-ace0-fbb531ad65f3

indications.c

@@ -318,6 +318,7 @@ static inline void free_zone(struct tone_zone* zone)
 		struct tone_zone_sound *tmp = zone->tones->next;
 		free((void*)zone->tones->name);
 		free((void*)zone->tones->data);
+		if (zone->ringcadance)
 			free((void*)zone->ringcadance);
 		free(zone->tones);
 		zone->tones = tmp;