WordPress Core Automatic Updates: Switch to a twicedaily cronjob to match the update check cron jobs, this removes the ability for update checks to continuously re-queue a upgrade job. See #22704

Built from https://develop.svn.wordpress.org/trunk@25466


git-svn-id: http://core.svn.wordpress.org/trunk@25387 1a063a9b-81f0-0310-95a4-ce76da25c4cd
WordPress Core Automatic Updates: Switch from using a transient for locking the upgrade process, to using a site option. See #22704

Built from https://develop.svn.wordpress.org/trunk@25467


git-svn-id: http://core.svn.wordpress.org/trunk@25388 1a063a9b-81f0-0310-95a4-ce76da25c4cd