mysql-test/r/create.result:
  A test case for foreign key bug that is resolved
mysql-test/r/select_found.result:
  test case for new select ... limit 0 behaviour
mysql-test/t/create.test:
  test case for foreign key bug that is fixed
mysql-test/t/select_found.test:
  test case for new behaviour of SELECT ... LIMIT 0
sql/sql_select.cc:
  SELECT ... LIMIT 0
sql/sql_union.cc:
  replacing my dirty hack with Sanja's "proper" fix