When using download_url(), if the resource supplies a Content-MD5 header, verify the downloaded file against it. Fixes #20074


git-svn-id: https://develop.svn.wordpress.org/trunk@25541 602fd350-edb4-49c9-b593-d223f7449a82
WordPress Core Automatic Updates: Add a filter as to whether or not to send the site administrator a summary of executed updates. Props JustinSainton. See #22704


git-svn-id: https://develop.svn.wordpress.org/trunk@25542 602fd350-edb4-49c9-b593-d223f7449a82