AMBARI-11377. Kerberos: display warning that the user must create/distribute principals and keytabs. (rlevas via yusaku)

ambari-web/app/controllers/main/admin/kerberos.js

@@ -385,6 +385,8 @@ App.MainAdminKerberosController = App.KerberosWizardStep4Controller.extend({
         },
         success: 'getSecurityTypeSuccess'
       })
+    } else if (Em.typeOf(callback)=== 'function') {
+      callback();
     }
   },