[FAB-1447] Broadcaster exits normally at EOF

Make broadcast.(*broadcaster).queueEnvelopes() exits normally when
it detects io.EOF at receiving a message from a client.

If the orderer forwards io.EOF to a Node SDK client,
Orderer.sendBroadcast() fails due to the error.

I observed this error when I deploy a large chaincode with
BATCHSIZE=1.

Fix Issue # FAB-1447.
https://jira.hyperledger.org/browse/FAB-1447

Signed-off-by: Tatsushi Inagaki <e29253@jp.ibm.com>
Change-Id: Icc6379bb04ceaab7ad463c0234d2419c34f8faca

orderer/common/broadcast/broadcast.go

@@ -22,6 +22,8 @@ import (
 	ab "github.com/hyperledger/fabric/protos/orderer"
 	"github.com/op/go-logging"
 
+	"io"
+
 	"github.com/golang/protobuf/proto"
 )
 
@@ -118,6 +120,9 @@ func (b *broadcaster) queueEnvelopes(srv ab.AtomicBroadcast_BroadcastServer) err
 		default:
 		}
 		msg, err := srv.Recv()
+		if err == io.EOF {
+			return nil
+		}
 		if err != nil {
 			return err
 		}