Since yum-deprecated is slowly removed from Fedora (in Fedora 23 is not
installed by default), we're forced to migrate to dnf. The main problem
with dnf here is lack of --downloaddir option
(https://bugzilla.redhat.com/show_bug.cgi?id=1279001). As nobody is
going to implement it, simply extract downloaded packages from cache
directory (thanks to provided config file, it is always /var/cache/yum).
This basically replaces "dom0-updates: use yum-deprecated instead of dnf
in all calls" with a set of workarounds for dnf missing parts.
Related to QubesOS/qubes-issues#1574
07c442f534