Bug#31030 rpl000015.test fails if $MYSQL_TCP_PORT != 3306
Note:
  This bug does not occur in MySQL 5.0 and up, because
  ChangeSet 1.2328.2.1 2006/11/27 for MySQL 5.0 prevents this.
  The 5.0 fix uses the environment variable DEFAULT_MASTER_PORT
  which is set by mysql-test-run.pl.
  mysql-test-run.pl in 4.1 does not set this variable.
  There are two alternatives:
  1) Backport the 5.0 fix for this test including modifications
     to mysql-test-run.pl and mysql-test-run-shell.
     This is a not acceptable impact on an old MySQL version.
  2) Fix the problem different than in 5.0 like in the current
     ChangeSet + do not apply these changes when upmerging to 5.0