Fix remaining lint error

Fix the following lint warning which was overlooked by the previous
attempt ( fb4897776f ).

manifests/ldap_backend.pp:338:WARNING: missing trailing comma after
last element

Change-Id: Ic9923929cb18857d2dd8cdc6684771d04fb36bfa
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

manifests/ldap_backend.pp

@@ -335,7 +335,7 @@ define keystone::ldap_backend(
     owner   => 'root',
     group   => $keystone::params::group,
     require => Anchor['keystone::config::begin'],
-    before  => Anchor['keystone::config::end']
+    before  => Anchor['keystone::config::end'],
   }
 
   keystone_domain_config {