the master but on the slave

MySQL can decide to "downgrade" a INSERT DELAYED statement
to normal insert in certain situations.
One such situation is when the slave is replaying a 
replication feed.
However INSERT DELAYED is logged even if there're no updates
whereas the NORMAL INSERT is not logged in such cases.

Fixed by always logging a "downgraded" INSERT DELAYED: even 
if there were no updates.


mysql-test/r/rpl_insert_delayed.result:
  Bug #29571: test case
mysql-test/t/rpl_insert_delayed.test:
  Bug #29571: test case
sql/sql_insert.cc:
  Bug #29571: log INSERT DELAYED even if it was 
  "downgraded" to INSERT (and there were no updates)