Adds default constructor to JabberAccountID in order to fix serialization error of JabberAccountRegistration.

src/net/java/sip/communicator/service/protocol/jabber/JabberAccountID.java

@@ -94,6 +94,14 @@ public JabberAccountID(String id, Map<String, String> accountProperties)
                 getServiceName(accountProperties));
     }
 
+    /**
+     * Default constructor for serialization purposes.
+     */
+    public JabberAccountID()
+    {
+        this(null, new HashMap<String, String>());
+    }
+
     /**
      * Returns the override phone suffix.
      *