Revert "dib-functests: run on bookworm"

This reverts commit 5256991346.

Reason for revert: dib-functests-arm64-deb is failing because of missing debootstrap/scripts/noble

Reverting to get back the role that downloads unstable debootstrap

Change-Id: I920f02e4a9a7751f9e1c58ccde9d0f766e185cd7

playbooks/dib-functests/run.yaml

@@ -5,5 +5,6 @@
     - bindep
     - dib-setup-gate-mirrors
     - ensure-podman
+    - dib-ensure-debootstrap
     - dib-functests
 

roles/dib-ensure-debootstrap/README.rst

@@ -0,0 +1,2 @@
+Update debootstap from debian unstable. This ensures debootstrap is new
+enough to recognize Noble.

roles/dib-ensure-debootstrap/tasks/main.yaml

@@ -0,0 +1,12 @@
+- name: Install debootstrap/unstable
+  # This is shell because doing it with native ansible modules went nowhere
+  become: yes
+  shell: |
+    set -ex
+    echo "APT::Default-Release: 'stable';" > /etc/apt/apt.conf.d/default-release
+    echo "deb http://deb.debian.org/debian unstable main" > /etc/apt/sources.list.d/unstable-debian.list
+    apt-get update
+    apt-get install -y debootstrap
+    # Remove the use of unstable as it seems to interfere with other tasks
+    rm /etc/apt/sources.list.d/unstable-debian.list
+    apt-get --assume-yes update