provide the writable datadir for mysqld --help (for lower_case test)
sql/log.h, sql/mysqld.cc
    make default binlog_format value to be 0 (for a hack of using
    GET_STR for enum to continue to work)


mysql-test/mysql-test-run.pl:
  provide the writable datadir for mysqld --help (for lower_case test)
sql/log.h:
  make default binlog_format value to be 0 (for a hack of using
  GET_STR for enum to continue to work)
sql/mysqld.cc:
  make default binlog_format value to be 0 (for a hack of using
  GET_STR for enum to continue to work)