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

@@ -7,10 +7,12 @@ class openstack_project::lists(
   $listdomain = 'lists.openstack.org'
 
   class { 'exim':
-    sysadmins       => $listadmins,
-    queue_interval  => '1m',
-    queue_run_max   => '50',
-    mailman_domains => [$listdomain],
+    sysadmins                => $listadmins,
+    queue_interval           => '1m',
+    queue_run_max            => '50',
+    mailman_domains          => [$listdomain],
+    smtp_accept_max          => '100',
+    smtp_accept_max_per_host => '10',
   }
 
   class { 'mailman':