log of JMS LinkedException when handling provider failure

the JMSException's linked exception data is quite useful to log when debugging issues related to integration with forein jms provider.

here a possible version of the required change in org.jboss.ejb.plugins.jms.JMSContainerInvoker:handleFailure()

public void handleFailure(Throwable t)
{
log.warn("JMS provider failure detected: ", t);
failure = t;

// Helpful to debug issues when WSMQ is the jms provider
if(t instanceof JMSException) {

Exception le = ((JMSException)t).getLinkedException();
if (le != null) {
log.trace("Linked exception: "+le);
log.trace("Linked exception: cause: "+le.getCause() );
}
}