Use non-alias-modifying mailman provider

Consume the mailman provider that does not overwrite /etc/aliases every
time. This should cut down on puppet fail noise.

Depends-On: I86bcbe2665dfa18d766a03a60263a37088a53b5c
Change-Id: Iaa2657208cae18afe0c26491afba04ff268a3d9a

modules/openstack_project/manifests/lists.pp

@@ -36,6 +36,10 @@ class openstack_project::lists(
     backup_server => 'ci-backup-rs-ord.openstack.org',
   }
 
+  Maillist {
+    provider    => 'noaliasmailman',
+  }
+
   maillist { 'openstack-es':
     ensure      => present,
     admin       => 'flavio@redhat.com',