fixed bug in timestamp replication

mysql-test/r/rpl000002.result:
  test timestamp replication
mysql-test/t/rpl000002.test:
  test timestamp replication

mysql-test/r/rpl000002.result

@@ -2,3 +2,7 @@ n
 2000
 2001
 2002
+id	created
+1	1970-01-01 06:25:45
+id	created
+1	1970-01-01 06:25:45

mysql-test/t/rpl000002.test

@@ -9,9 +9,26 @@ save_master_pos;
 connection slave;
 use test;
 sync_with_master;
-@r/rpl000002.result select * from t1;
+select * from t1;
 connection master;
 drop table t1;
 save_master_pos;
 connection slave;
 sync_with_master;
+slave stop;
+connection master;
+drop table if exists t2;
+create table t2(id int auto_increment primary key, created datetime);
+set timestamp=12345;
+insert into t2 set created=now();
+select * from t2;
+save_master_pos;
+connection slave;
+slave start;
+sync_with_master;
+select * from t2;
+connection master;
+drop table t2;
+save_master_pos;
+connection slave;
+sync_with_master;

sql/slave.cc

@@ -857,6 +857,7 @@ static int exec_event(THD* thd, NET* net, MASTER_INFO* mi, int event_len)
   
     thd->server_id = ev->server_id; // use the original server id for logging
     thd->set_time();				// time the query
+    if(!ev->when)
       ev->when = time(NULL);
     
     switch(type_code) {