Bug #25074 mysql_upgrade test can't give consistent results  - Tell the programs executed by mysql_upgrade to only read   from the defaults file generated by msyql_upgrade  - Fix memory leaks
Bug #25074 mysql_upgrade test can't give consistent results
 - Tell the programs executed by mysql_upgrade to only read
  from the defaults file generated by msyql_upgrade
 - Fix memory leaks


client/mysql_upgrade.c:
  - Always generate defaults file used for the programs executed
    by mysql_upgrade.
  - Set the executed programs to read options _only_ from the
    generated defaults file 
  - Add DBUG printouts
  - Add comments
  - Fix memory leaks
  - Change one 'my_delete'(delete a file) to 'my_free'(free memory)
  - Free memory allocated by 'load_default'

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