BUG#30274 (Debug server crashes because mutex isn't initialized):
BUG#30274 (Debug server crashes because mutex isn't initialized):

Completion patch, since it is possible that Log_event::write_header()
is called with no current thread.

When starting the server, there is no thread available, but
MYSQL_BIN_LOG::open() is called to initialize the binary log. The
function writes a format description log event to the binary log,
which means that Log_event::write_header() can be called with no
current thread object available.


sql/log_event.cc:
  Since Log_event::write_header() can be called from inside
  init_server_components(), it is possible that thd is NULL. In this
  case, we set the time of the event to the current time instead
  of the start time of the query.

natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,davidl-zend/zenddbi,flynn1973/mariadb-aix,davidl-zend/zenddbi,natsys/mariadb_10.2,davidl-zend/zenddbi,ollie314/server,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,slanterns/server,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi