Use new CDN endpoint for meek-azure
An account problem has left meek-azure not working for a couple of days. I had to upgrade to another kind of Azure account and the CDN settings did not migrate with it. The crucial problem is the CDN endpoint domain name, az668014.vo.msecnd.net, that is stranded under an expired account. I set up a new equivalent CDN domain, az786092.vo.msecnd.net, but it needs a change to bridge_prefs.js.