I need this fix because my packaging of librepo is now failing because when the unit tests are being run, the import of xattr fails because cffi isn't installed on Tumbleweed.

@TheBlackCat, @alarrosa, @aledr, @aplanas, @cyberiad, @dirkmueller, @matejcik, @posophe, @rjschwei, @sleep_walker, @tbechtold: review reminder