Minor fix.

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@3754 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/wildfire/pubsub/PubSubPersistenceManager.java

@@ -1200,6 +1200,9 @@ public class PubSubPersistenceManager {
     }
 
     private static Collection<JID> decodeJIDs(String jids) {
+        if (jids == null) {
+            return Collections.emptyList();
+        }
         Collection<JID> decodedJIDs = new ArrayList<JID>();
         StringTokenizer tokenizer = new StringTokenizer(jids, ",");
         while (tokenizer.hasMoreTokens()) {