I hope this is a temporary error and it will be back in the next release. Exporting to Flickr from Revel is a major part of my workflow and I'd have to reconsider my premium sub if it's been permanently removed.
We had to remove Flickr support from 1.8 so Apple wouldn't reject our app. Flickr's auth dialog had links that eventually took users to purchase a Flickr subscription direct from Yahoo. Apparently this has affected other apps. Flickr has said they're working on an updated dialog that doesn't have the problematic links, but it's not ready yet.