auto-commit on Xid_log_event


client/mysqlbinlog.cc:
  auto-ROLLBACK if binlog was not closed properly.
mysql-test/r/ctype_ucs.result:
  results updated
mysql-test/r/mix_innodb_myisam_binlog.result:
  results updated
mysql-test/r/mysqlbinlog2.result:
  results updated
mysql-test/r/rpl_relayrotate.result:
  results updated
mysql-test/r/user_var.result:
  results updated
mysql-test/t/ctype_ucs.test:
  finalize binlog before calling mysqlbinlog
mysql-test/t/user_var.test:
  finalize binlog before calling mysqlbinlog
sql/log_event.cc:
  commit at Xid_log_event
  comments edited
sql/mysqld.cc:
  free(0) fixed
sql/slave.cc:
  rollback at fake Rotate_log_event
sql/sql_class.h:
  no commit_or_rollback argument for binlog->write(THD *thd, IO_CACHE *cache)
sql/log.cc:
  don't write "COMMIT" query, Xid_log_event is enough
sql/log_event.h:
  more comments for LOG_EVENT_BINLOG_IN_USE_F
  LOG_EVENT_FORCE_ROLLBACK_F added
sql/sql_repl.cc:
  rollback at Rotate_log_event.
  don't consider binlog corrupted if it was open when we read Formar_description but closed when we got to the end
sql/sql_repl.h:
  style fix