Drop the relabel flag for bind-mount

Since this bind-mount isn't shared with any other container, remove its
"relabel" flag (:z).

This relabelling is especially useless since the directory creation AND
openstack-selinux sets its type to a sensible value. We can therefore
remove it and prevent possible issues in the future.

Closes-Bug: #1888216
Change-Id: I1e7ddb3bbb3825db805f137ea9a2501878f380d4
(cherry picked from commit 98d2271)

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

@@ -718,7 +718,7 @@ outputs:
                   - /var/run/libvirt:/var/run/libvirt:shared,z
                   - /var/lib/libvirt:/var/lib/libvirt:shared,z
                   - /var/log/libvirt/qemu:/var/log/libvirt/qemu:ro
-                  - /var/lib/vhost_sockets:/var/lib/vhost_sockets:z
+                  - /var/lib/vhost_sockets:/var/lib/vhost_sockets
                   - /var/lib/nova:/var/lib/nova:shared
                 -
                   if: