When opening/creating the transaction coordinator's log, if binlog is
used, the tc log is the binlog so we use the binlog's name; otherwise
we use the mmap-based log, named after the mandatory argument of the
--log-tc option (meant for that).


sql/log.cc:
  fixing wrong order of arguments to my_create()
  (3rd param is the desired modes of the file; "0" lead to no rights
  for anybody on the file).
sql/mysqld.cc:
  When opening/creating the transaction coordinator's log, if binlog is
  used, the tc log is the binlog so we use the binlog's name; otherwise
  we use the mmap-based log, named after the mandatory argument of the
  --log-tc option (meant for that).