load_metadata_for_topics should raise exceptions on explicit topic args
Raise UnknownTopicOrPartitionError immediately in ensure_topic_exists -- server is not auto-creating
Use standard exceptions in client._get_leader_for_partition()
- drop custom PartitionUnavailable exception
- raise UnknownTopicOrPartitionError or LeaderNotAvailableError
- add tests for exception raises
Add test for sending produce request to unknown topic w/o auto-creation