Fire the wp_cron action from init instead of sanitize_comment_cookies so that...

Fire the wp_cron action from init instead of sanitize_comment_cookies so that cron handlers can rely on a fully initialized env. Props SergeyBiryukov, norocketsurgeon. fixes #19818


git-svn-id: https://core.svn.wordpress.org/trunk@20652 1a063a9b-81f0-0310-95a4-ce76da25c4cd