Logging can be confusing when using fallback replication stream methods

When the log includes something like:

DEBUG starting streaming from LSN '...'
DEBUG Could not register for streaming, retrying without optional options ...

Users get concerned that streaming may not be running since the latter debug/warn messages tend to raise cause for concern. It might be worth adding a log entry when the fallback approaches succeed (or perhaps just by default when we do create the ReplicationStream) that everything is fine?

See https://gitter.im/debezium/user?at=5d7c01c205fd3716951ded95