fix invalid read

srcs/ft_print_strings.c

@@ -35,11 +35,13 @@ t_dlist *get_first(void)
 
 void clean_list(void)
 {
+    t_dlist *tmp = list;
     while (list)
     {
+        tmp = list;
         free(list->content);
         free(list);
-        list = list->previous;
+        list = tmp->previous;
     }
     list = NULL;
 }