Also set persist items to true in PubSubIntegrationTest

smack-integration-test/src/main/java/org/jivesoftware/smackx/pubsub/PubSubIntegrationTest.java

@@ -58,6 +58,7 @@ public class PubSubIntegrationTest extends AbstractSmackIntegrationTest {
         // items do not need payload, to prevent payload-required error responses when
         // publishing the item.
         config.setDeliverPayloads(false);
+        config.setPersistentItems(true);
         Node node = pubSubManagerOne.createNode(nodename, config);
         try {
             LeafNode leafNode = (LeafNode) node;