FAB-5331 Fix formatting of channel name

Historically, gossip keeps the channel name in messages
[]byte instead of in *string*s.

There is a String() method that formats complex messages
It would be beneficial to print instead a string,
for usability of log parsing.

Change-Id: I71351fa324d6e1ca583588dab089a9e887996f7f
Signed-off-by: yacovm <yacovm@il.ibm.com>

protos/gossip/extensions.go

@@ -535,7 +535,7 @@ func (m *SignedGossipMessage) String() string {
 			isSimpleMsg = true
 		}
 		if !isSimpleMsg {
-			desc := fmt.Sprintf("Channel: %v, nonce: %d, tag: %s", m.Channel, m.Nonce, GossipMessage_Tag_name[int32(m.Tag)])
+			desc := fmt.Sprintf("Channel: %s, nonce: %d, tag: %s", string(m.Channel), m.Nonce, GossipMessage_Tag_name[int32(m.Tag)])
 			gMsg = fmt.Sprintf("%s %s", desc, gMsg)
 		}
 	}