Modified #getChildElementXML to include possible extensions

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@2263 b35dd754-fafc-0310-a699-88a17e54d16e

source/org/jivesoftware/smack/packet/Registration.java

@@ -181,6 +181,8 @@ public class Registration extends IQ {
                 buf.append("</").append(name).append(">");
             }
         }
+        // Add packet extensions, if any are defined.
+        buf.append(getExtensionsXML());
         buf.append("</query>");
         return buf.toString();
     }