copr-be-dev: use image-builder for uploads to libvirt

There is a small bug in the `image-builder upload` code, causing it to always
use the "default" libvirt pool. I am proposing a fix here
https://github.com/osbuild/images/pull/2147
and I uploaded the current builder images with the patched version.

roles/copr/backend/templates/provision/copr-upload-builder-images.j2

@@ -131,8 +131,13 @@ for task in "${tasks[@]}"; do
     case $1 in
     libvirt)
         conn=$2 ; file=$3 ; name=$4
-        virsh --connect="$conn" vol-create-as --pool images "$name" 1M
-        virsh --connect="$conn" vol-upload    --pool images "$name" --sparse "$file"
+        image-builder upload \
+            "$file" \
+            --arch "$arch" \
+            --to libvirt \
+            --libvirt-connection "$conn" \
+            --libvirt-pool images \
+            --libvirt-volume "$name"
         ;;
     osuosl)
         name=$2 ; file=$3