Index: modules/web/manifests/server.pp
===================================================================
--- a/modules/web/manifests/server.pp
+++ b/modules/web/manifests/server.pp
@@ -145,9 +145,16 @@
     mode => 755,
   }
 
+  $update_cms_cmd = [
+    "hg", "pull",
+    "--quiet",
+    "--update",
+    "--repository", "/opt/cms",
+  ]
+
   cron {'update_cms':
     ensure => present,
-    command => "hg pull -q -u -R /opt/cms",
+    command => shellquote($update_cms_cmd),
     minute  => '4-59/20',
   }