Openfire should return "msgoffline" in disco requests (as per XEP-0160)

src/java/org/jivesoftware/openfire/OfflineMessageStrategy.java

@@ -20,10 +20,13 @@
 
 package org.jivesoftware.openfire;
 
+import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.jivesoftware.openfire.container.BasicModule;
+import org.jivesoftware.openfire.disco.ServerFeaturesProvider;
 import org.jivesoftware.openfire.privacy.PrivacyList;
 import org.jivesoftware.openfire.privacy.PrivacyListManager;
 import org.jivesoftware.openfire.user.UserManager;
@@ -40,7 +43,7 @@ import org.xmpp.packet.PacketExtension;
  *
  * @author Iain Shigeoka
  */
-public class OfflineMessageStrategy extends BasicModule {
+public class OfflineMessageStrategy extends BasicModule implements ServerFeaturesProvider {
 
 	private static final Logger Log = LoggerFactory.getLogger(OfflineMessageStrategy.class);
 
@@ -241,6 +244,18 @@ public class OfflineMessageStrategy extends BasicModule {
         }
     }
 
+    @Override
+    public Iterator<String> getFeatures() {
+        switch (type) {
+            case store:
+            case store_and_bounce:
+            case store_and_drop:
+                // http://xmpp.org/extensions/xep-0160.html#disco
+                return Collections.singleton("msgoffline").iterator();
+        }
+        return Collections.<String>emptyList().iterator();
+    }
+
     /**
      * Strategy types.
      */