general: no INSERT delayed usage

* No longer uses INSERT DELAYED, since, beginning with MySQL 5.5.7,
  INSERT DELAYED is always handled as a simple INSERT (that is,
  without the DELAYED option) whenever the value of binlog_format is
  STATEMENT or MIXED. (In the latter case, the statement no longer
  triggers a switch to row-based logging, and so is logged using the
  statement-based format.)
  (closes #2268)

Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reported-by: Thorsten Schwander <thorsten.schwander@gmail.com>