add sql_mode to mysql.event
WL#1034 (Internal CRON)


mysql-test/lib/init_db.sql:
  partial fix for bug#16407 (sql_mode not regarded)
  add sql_mode to mysql.event
mysql-test/r/system_mysql_db.result:
  partial fix for bug#16407 (sql_mode not regarded)
  add sql_mode to mysql.event
scripts/mysql_create_system_tables.sh:
  partial fix for bug#16407 (sql_mode not regarded)
  add sql_mode to mysql.event
scripts/mysql_fix_privilege_tables.sql:
  partial fix for bug#16407 (sql_mode not regarded)
  add sql_mode to mysql.event