ci: stable-only: explicitly pin centos build

On older CI nodes, we cannot use centos dib images in the pipeline
without explicitly pulling in an older image of centos because newer
centos images use an XFS feature in them which prevents us from
extracting image contents.

Change-Id: Ic14e75071651551c663a97d98c2226f8a375ec0b

devstack/lib/ironic

@@ -2865,6 +2865,11 @@ function build_ipa_dib_ramdisk {
     if is_deploy_iso_required; then
         IRONIC_DIB_RAMDISK_OPTIONS+=" iso"
     fi
+    if [[ "centos" =~ "$IRONIC_DIB_RAMDISK_OPTIONS" ]]; then
+        # NOTE(TheJulia): This is kind of awful, but XFS in newer centos
+        # images breaks on older ubuntu.
+        DIB_CLOUD_IMAGES="https://cloud.centos.org/centos/9-stream/x86_64/images/CentOS-Stream-GenericCloud-9-20240101.0.x86_64.qcow2"
+    fi
     git_clone $IRONIC_PYTHON_AGENT_BUILDER_REPO $IRONIC_PYTHON_AGENT_BUILDER_DIR $IRONIC_PYTHON_AGENT_BUILDER_BRANCH
     ELEMENTS_PATH="$IRONIC_PYTHON_AGENT_BUILDER_DIR/dib" \
         DIB_DHCP_TIMEOUT=$IRONIC_DIB_DHCP_TIMEOUT \
@@ -2873,6 +2878,7 @@ function build_ipa_dib_ramdisk {
         DIB_REPOREF_ironic_python_agent=$TARGET_BRANCH \
         DIB_REPOLOCATION_requirements="$DEST/requirements" \
         DIB_REPOREF_requirements=$TARGET_BRANCH \
+        DIB_CLOUD_IMAGES=${DIB_CLOUD_IMAGES:-} \
         disk-image-create "$IRONIC_DIB_RAMDISK_OPTIONS" \
         -x -o  "$tempdir/ironic-agent" \
         ironic-python-agent-ramdisk