Split upgrade stage and add dpkg cleanup

Avoid problems if one or more nodes are upgrading libvirt/QEMU and live
migrations fail.

oneshot/update-pvc-cluster.yml

@@ -48,6 +48,13 @@
         state: "absent"
         force: "yes"
 
+- hosts: all
+  remote_user: deploy
+  become: yes
+  become_user: root
+  gather_facts: yes
+  serial: 1
+  tasks:
     - name: check freshness
       command: /usr/sbin/needrestart -p
       register: freshness