Fetch compatibile dnf download command in functest setup

The dnf-plugins-core repo updates its download command to use a
dnf.utils method that is not present in the dnf version installed by
Debian packages. Update the fetch of dnf-plugins-core to use the last
version of the download plugin that is compatible with the dnf package
in Debian.

Note that we don't use the bookworm dnf-plugins-core package to address
this because dnf-plugins-core specifies that it breaks and replaces
zypper. This occurs due to the collision of a single manpage filename.
OpenSUSE addresses this by moving one of the manpages to a different
location allowing zypper and dnf to be installed together on SUSE
distros. Hopefully Debian will manage to do similar eventually.

Change-Id: I3a029340f9635f54570e48a68a9e2c1b1e30a76f

roles/dib-functests/tasks/main.yaml

@@ -34,13 +34,17 @@
     state: directory
     mode: ugo+rw
 
-# NOTE(ianw) 2021-10-15 : at this point dnf-plugins-core is stuck in
-# the NEW queue.  Use that when it is available over this hack,
-# obviously.
+# There is a Debian package for dnf-plugins-core but it breaks and replaces
+# zypper which we also want to install. Prior to dnf-plugins-core existing
+# in Debian we fetched the content we needed from github. Continue doing
+# that but pin the version for compatibility with Debian's dnf.
+# Until Debian fixes its dnf-plugins-core package in bookworm; manually
+# install "dnf download" for the yum-minimal element. Note version 4.4.4
+# is the last version compatible with bookworm's dnf package.
 - name: Install dnf download
   shell: |
       set -x
-      git clone https://github.com/rpm-software-management/dnf-plugins-core
+      git clone --depth 1 --branch 4.4.4 https://github.com/rpm-software-management/dnf-plugins-core
       mkdir /usr/lib/python3/dist-packages/dnf-plugins
       cp -r dnf-plugins-core/plugins/dnfpluginscore /usr/lib/python3/dist-packages
       cp dnf-plugins-core/plugins/download.py /usr/lib/python3/dist-packages/dnf-plugins