[ceph] Deploy ceph failed at controller node for multiple node

Controller node wouldn't install libvirt package. The package will only
been installed at nodes which had enable nova-compute.
We only need to configure libvirt secret if it had enable nova-compute.

Change-Id: I9cd6baf1820ce9f71c276d7e8b670307833578a5
Closes-Bug: 1515960
diff --git a/extras.d/60-ceph.sh b/extras.d/60-ceph.sh
index 38b901b..cc90128 100644
--- a/extras.d/60-ceph.sh
+++ b/extras.d/60-ceph.sh
@@ -32,7 +32,7 @@
             echo_summary "Configuring Cinder for Ceph"
             configure_ceph_cinder
         fi
-        if is_service_enabled cinder || is_service_enabled nova; then
+        if is_service_enabled n-cpu; then
             # NOTE (leseb): the part below is a requirement to attach Ceph block devices
             echo_summary "Configuring libvirt secret"
             import_libvirt_secret_ceph