PostConstruct callback should be allowed in stateful session bean.

In current trunk call back check code:

org.apache.openejb.config.rules.CheckCallbacks.checkCallback(Class<?>, String, CallbackMethod, EnterpriseBean, Class...)
{
....
if (sb.getSessionType().equals(SessionType.STATELESS)) {
if (!callback.getMethodName().equals("ejbCreate"))

{ fail(bean.getEjbName(), "callback.sessionbean.invalidusage", type, callback.getMethodName(), ejbClass); }

} else

{ fail(bean.getEjbName(), "callback.sessionbean.invalidusage", type, callback.getMethodName(), ejbClass); }

...
}

so that when a post construct callback is used in statefull session bean. openejb will throw validate failure exception.