Remove unused maxRetryAttempts and retrySleep

Currently maxRetryAttempts and retrySleep are wired throughout the code, but don't actually hook up to anything. The handling should be removed to make it clear that these aren't used anywhere.

There is no backwards compatibility issue here since the parsing is lazy - its not a required field so if a user is specifying it will be silently ignore. Just like it is silently ignored today.