mysql-test/README.suites:
  removed. it was turned into a manual, eventually
mysql-test/include/default_mysqld.cnf:
  use normal environment variables instead of magic @OPT.vardir
mysql-test/lib/My/ConfigFactory.pm:
  use normal environment variables instead of magic @OPT.vardir
mysql-test/mysql-test-run.pl:
  initialize environment variables before parsing the first my.cnf template - it may refer to them
mysql-test/suite/sphinx/my.cnf:
  use normal environment variables instead of magic @OPT.vardir