It's not possible anymore to use latest-RHEL-$major in the URLs, it's necessary to also supply the minor version for rel-eng composes. Also the URL structure had to be updated due to changes on the download servers. Related: rhbz#1828808
- add test coverage for rhbz#1650363 - cherry-picked from 5322664432 Related: rhbz#1785159
5322664432