Making sure virt-guest-shutdown.target exists

libvirt-daemon is part of the default overcloud image but it's also
possible that it's not installed or simply removed by operators. In this
case, tripleo_nova_libvirt_guests will fail.

Related: https://bugzilla.redhat.com/1810319
Change-Id: I0814bd8794ab82792837b27d0128e15c34b90adc

deployment/nova/nova-compute-container-puppet.yaml

@@ -1081,6 +1081,13 @@ outputs:
 
                     [Install]
                     WantedBy=multi-user.target
+              - name: Making sure virt-guest-shutdown.target is present
+                copy:
+                  dest: /etc/systemd/system/virt-guest-shutdown.target
+                  content: |
+                    [Unit]
+                    Description=Libvirt guests shutdown
+                    Documentation=https://libvirt.org
               - name: libvirt-guests enable VM shutdown on compute reboot/shutdown
                 systemd:
                   name: libvirt-guests
@@ -1115,6 +1122,13 @@ outputs:
 
                     [Install]
                     WantedBy=multi-user.target
+              - name: Making sure virt-guest-shutdown.target is present
+                copy:
+                  dest: /etc/systemd/system/virt-guest-shutdown.target
+                  content: |
+                    [Unit]
+                    Description=Libvirt guests shutdown
+                    Documentation=https://libvirt.org
               - name: tripleo_nova_libvirt_guests enable VM shutdown on compute reboot/shutdown
                 systemd:
                   name: tripleo_nova_libvirt_guests