Connection retries should be limited to cases where it could succeed

[smoyer64]

Currently the client attempts to connect to the message queue repeated even when:

• The broker.url is invalid (bad scheme was tested)
• broker.username and broker.password don't authenticate
• queue.name is invalid (not tested)

If the parameters passed to the client are valid, then retries are prudent - if the parameters are invalid, then the client should abort loudly.