LP:737111 - Different behavior for TIMESTAMPADD with 0000-00-00 argument in 5.1-micro

In 5.1-micro , applying TIMESTAMPADD on a column that contains a value of "0000-00-00" returns "0000-00-00". In mysql-5.1, it returns NULL.

Test case:

CREATE TABLE t1 (f1 date);
INSERT INTO t1 VALUES ('0000-00-00');

SELECT TIMESTAMPADD( WEEK, 1, f1 ) FROM t1;