Add RDO mirror

Now that we actually have the latest RDO packages, use the mirror
hosted inside the OpenStack infrastructure.

Change-Id: I6c800dcd5b3fc6f7cc1c1e0777d93ab40c6a5e09

common-tasks/test-set-nodepool-vars.yml

@@ -32,6 +32,7 @@
         echo "pip_wheel_mirror=${NODEPOOL_WHEEL_MIRROR}"
         echo "centos_epel_mirror=${NODEPOOL_EPEL_MIRROR}"
         echo "galera_percona_xtrabackup_repo_host=${NODEPOOL_PERCONA_PROXY}"
+        echo "openstack_hosts_rdo_mirror_url=${NODEPOOL_RDO_PROXY}"
         if [[ ${NODEPOOL_PYPI_MIRROR} == *.ovh.* ]]; then
           echo "nova_virt_type=qemu"
         fi