Fail group assignment if metadata request fails (issues #632)
Fail group assignment if metadata request fails (issues #632)

orthrus/librdkafka,janmejay/librdkafka,senior7515/librdkafka,orthrus/librdkafka,orthrus/librdkafka,janmejay/librdkafka,orthrus/librdkafka,janmejay/librdkafka,janmejay/librdkafka,senior7515/librdkafka,senior7515/librdkafka,senior7515/librdkafka