Clean up some implementation aspects of the Fedora distro definition:
- Do not have default Fedora distro version and use `fedora` as the
package name in all places that use it, instead of `fedora33`.
- Fix bugs when wrong (Fedora 33) values were returned by `OSTreeRef()`
and `Releasever()` for newer Fedora releases.
- Test Fedora 35 in package unit tests.
- Add unit test for `OSTreeRef()` method.
- Use architecture name constants from `distro` package, instead of
string literals.
Fix#1802
Signed-off-by: Tomas Hozza <thozza@redhat.com>
b9efe82bd7