no rows of the blackhold engine (for this engine to be a binlog propagator).
NOTE: blackhole.test currently hangs in 5.0 BUG#10175 so I'll merge without running this test; the
person who fixes the hang will correct the merged blackhole.result or ask me to).


mysql-test/r/blackhole.result:
  result update
mysql-test/t/blackhole.test:
  checking that statements get into binlog even when they were affecting
  no rows of the blackhold engine. So that this engine can serve as
  a binlog propagator (A->B->C replication where B has only blackhole tables,
  B receives binlog from A, applies it to blackhole tables, writes statements
  to its binlog which it sends to C; both A and C have non-blackhole tables). B is just a proxy.