Bug#26687 rpl_ddl test fails if run with --innodb option
  Details:
  - The current test + the expected results do only fit
    if the slave uses MyISAM for mysqltest1.t1.
    Therefore skip the test if we do not meet these
    conditions.
  - The solution for 5.1 will look quite different
    because "ps_ddl" is already much improved in
    MySQL 5.1.