Merge pull request #264 from Shopify/check-leader-connected

When we get a new leader, check it is connected

producer.go

@@ -367,6 +367,10 @@ func (p *Producer) leaderDispatcher(topic string, partition int32, input chan *M
 			return err
 		}
 
+		if _, err = leader.Connected(); err != nil {
+			return err
+		}
+
 		output = p.getBrokerWorker(leader)
 		return nil
 	}