[Git Pull request] Remove unused and confusing default broker url

Hi,

I was testing with the simple producer and consumer, my colleague got confused by the default broker url, as it is not actually used, these 2 patches just remove it.
He tried changing the broker url in the code, and it worked only because he still used the mq-west and mq-east as groups.
Obviously it can only be changed in the jndi.properties file.