Move resolvconf JIT execution to common tasks

Use include_role in a common-tasks include to execute the resolvconf
role when unbound is used.

Change-Id: Id70f3d5dc66701a1fb593e6309b071d0e38ea282

playbooks/os-nova-install.yml

@@ -13,12 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- include: common-playbooks/unbound-clients.yml
-  vars:
-    unbound_group: "nova_all"
-  when:
-    - resolvconf_enabled | bool
-
 - name: Prepare MQ/DB services
   hosts: nova_conductor
   gather_facts: no