Fix for BUG#7658 "optimize crashes slave thread (1 in 1000)]": mysql_admin_table() attempted to write to a vio which was 0. I could have fixed mysql_admin_table() but fixing my_net_write() looked more future-proof.
Fix for BUG#7658 "optimize crashes slave thread (1 in 1000)]":
mysql_admin_table() attempted to write to a vio which was 0. I could have fixed mysql_admin_table()
but fixing my_net_write() looked more future-proof.

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