mysql_fix_privilege_tables.s's ability to convert the system tables as of
3.20 to current system table format
Add similar test for 4.1.23 tables - but use "mysql < mysql_fix_privilege_tables.sql"
so it can be run on any platform. 


mysql-test/t/system_mysql_db_fix30020-master.opt:
  Rename: mysql-test/t/system_mysql_db_fix-master.opt -> mysql-test/t/system_mysql_db_fix30020-master.opt
mysql-test/mysql-test-run.pl:
  Find mysql_fix_privilege_tables.sql and assign it's path and name to $MYSQL_FIX_PRIVILEGE_TABLES
mysql-test/t/system_mysql_db_fix30020.test:
  Send output to var/log/system_mysql_db_fix30020.err
  Add some more comments
mysql-test/t/system_mysql_db_fix40123-master.opt:
  New BitKeeper file ``mysql-test/t/system_mysql_db_fix40123-master.opt''
mysql-test/t/system_mysql_db_fix40123.test:
  New BitKeeper file ``mysql-test/t/system_mysql_db_fix40123.test''