Event hash mismatches cause perpetually failed events

Scenario: Somebody does a Search/Replace on the DB, and replaces say `wp_` with `wp_3`. Other problems with that aside, events in the cron control table now have an action of `wp_4_update_themes` but a hash of `1415f2766f26fbe75db22be4aae62aeb`(which was made from wp_update_themes).

Since get-due-batch re-hashed before sending (`md5( $event['action'] )`), the runner will then pass the new hash. But said event won't be found and the job will fail. However, the event is still due and at the top of the "due now" list. So the runner will keep trying over and over again to run the doomed event each batch.