This saves one byte per Query_log_event on disk compared to 5.0.[0..3]. Compatibility problems with 5.0.x where x<4
are explained in the comments in log_event.cc. Putting back s/my_open(O_TRUNC)/(my_delete+my_create) change which had
been wiped away by somebody doing a wrong 4.1->5.0 merge (which happened just
before 5.0.3 :( ). Applying it to new events for LOAD DATA INFILE.
If slave fails in Execute_load_query_log_event::exec_event(),
don't delete the file (so that it's re-usable at next START SLAVE).
And (youpi!) fix for BUG#3247 "a partially completed LOAD DATA INFILE is not
executed at all on the slave" (storing an Execute_load_query_log_event
to binlog, with its error code, instead of Delete_file_log_event).


mysql-test/r/mix_innodb_myisam_binlog.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_change_master.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_deadlock.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_error_ignored_table.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_flush_log_loop.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_loaddata.result:
  we now use one less byte when storing the catalog in binlog so positions change.
  Plus testing replication of LOAD DATA INFILE if duplicate key and non-transactional table.
mysql-test/r/rpl_log.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_max_relay_size.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_relayrotate.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_replicate_do.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_rotate_logs.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/r/rpl_until.result:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/t/mysqlbinlog.test:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/t/mysqlbinlog2.test:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/t/rpl_deadlock.test:
  we now use one less byte when storing the catalog in binlog so positions change
mysql-test/t/rpl_loaddata.test:
  we now use one less byte when storing the catalog in binlog so positions change.
  Plus testing replication of LOAD DATA INFILE if duplicate key and non-transactional table.
mysql-test/t/rpl_until.test:
  we now use one less byte when storing the catalog in binlog so positions change
sql/log_event.cc:
  a) We now store the catalog in Query_log_event in binlog WITHOUT its end zero.
  This saves one byte per Query_log_event on disk. Compatibility problems with 5.0.x where x<4
  are explained in the comments in this file.
  b) putting back s/my_open(O_TRUNC)/(my_delete+my_create) change which had
  been wiped away by somebody doing a wrong 4.1->5.0 merge (which happened just
  before 5.0.3 :( ). Applying it to new events for LOAD DATA INFILE.
  c) if slave fails in Execute_load_query_log_event::exec_event(),
  don't delete the file (so that it's re-usable at next START SLAVE).
sql/log_event.h:
  We now store the catalog in Query_log_event in binlog WITHOUT its end zero.
  This saves one byte per Query_log_event on disk. This new storage for
  the catalog is denoted by Q_CATALOG_NZ_CODE (couldn't re-use Q_CATALOG_CODE
  as 5.0.3 slaves of this 5.0.4 master would segfault because it would
  expect a 0 when there is none.
  Renaming get_open_mode() to get_create_or_append() (see log_event.cc)
sql/sql_load.cc:
  Fix for BUG#3247: if LOAD DATA INFILE fails but has permanently updated a table
  (i.e. has deleted/added/modified some rows in a non-transactional table),
  we must write an Execute_load_query_log_event to binlog (with the error code,
  as this class beautifully inherits from Query_log_event, it can store
  the error code - thanks Dmitri) and not a Delete_file_log_event (we use
  to write a Delete_file_log_event: no update happened on slave, bug).