Ignore event scheduler when checking long updates

https://code.google.com/p/mysql-master-ha/issues/detail?id=28

The event scheduler shouldn't prevent a failover, and should be ignored by the long updates check.  

The event status needn't be monitored by MHA, and should be handled on failover via the hooks in the master_ip_failover_script and master_ip_online_change_script.