Make sure resolvconf is enabled

This should be the default, but for some reason, it isn't on some
of our servers, especially older ones.

Change-Id: I1b926bb5583121123f261eb78a95f5cc5ce67273

modules/unbound/manifests/init.pp

@@ -39,6 +39,12 @@ class unbound (
       ensure  => present,
       require => File['/etc/default/unbound'],
     }
+
+    # Make sure resolvconf is enabled (which is the default).
+    exec {'enable-resolvconf':
+      command => '/sbin/resolvconf --enable-updates',
+      creates => '/var/run/resolvconf/enable-updates',
+    }
   }
 
   # Ubuntu uses resolvconf which will update resolv.conf to point to