Raise smtp_accept_max for openstack_project::lists

Increase Exim's smtp_accept_max on the listserv from its default 20
to allow handling more concurrent inbound delivery connections, but
also set a reasonably low per-host max to avoid any one sender
performing a denial of service.

Change-Id: I6691e8ddf8ce9911344359d65bb2f812cd85c4c9
Depends-On: I5519f6c28c81a6f40c78551ac318b91cacfc04fb

modules/openstack_project/manifests/lists.pp

@@ -11,6 +11,8 @@ class openstack_project::lists(
     queue_interval           => '1m',
     queue_run_max            => '50',
     mailman_domains          => [$listdomain],
+    smtp_accept_max          => '100',
+    smtp_accept_max_per_host => '10',
   }
 
   class { 'mailman':