"Federated INSERT failures"
  Federated does not correctly handle "INSERT...ON DUPLICATE KEY UPDATE"
  However, implementing such support is not reasonably possible without
  increasing complexity of the storage engine: checking that constraints
  on remote server match local server and parsing error messages.
  This patch causes 'ON DUPLICATE KEY' to fail with ER_DUP_KEY message
  if a conflict occurs and not to fail silently.


include/my_base.h:
  bug25511
    new storage engine hint: HA_EXTRA_INSERT_WITH_UPDATE
mysql-test/r/federated.result:
  test for bug25511
mysql-test/t/federated.test:
  test for bug25511
sql/ha_federated.cc:
  bug25511
    implement support for handling HA_EXTRA_INSERT_WITH_UPDATE hint
sql/ha_federated.h:
  bug25511
    new property: insert_dup_update
sql/sql_insert.cc:
  bug25511
    implement support for HA_EXTRA_INSERT_WITH_UPDATE
    When checking duplicates flag, if it is DUP_UPDATE, send hint
    to the storage engine.