Fixed memory leak

Fixed memory leak in test_head_list

src/util/list.h

@@ -76,12 +76,12 @@ void for_each_list(list_t *list, listIterator iterator);
 /**
 @brief Returns the head of the list (optionally removing it at the same time).
 */
-void head_list(list_t *list, void **element, bool removeFromList);
+void *head_list(list_t *list, bool removeFromList);
 
 /**
 @brief Returns the tail of the list.
 */
-void tail_list(list_t *list, void *element);
+void *tail_list(list_t *list);
 
 
 #if defined(__cplusplus)