[FAB-4744] Remove unused code from gossip/comm

There are few variables and unused values in gosisp communication module
which could be cleaned up, this commit takes care to remove them.

Change-Id: Ibedcfce97ac480afbdb465969ce99c1d3b60559a
Signed-off-by: Artem Barger <bartem@il.ibm.com>

gossip/comm/comm_impl.go

@@ -155,7 +155,6 @@ type commImpl struct {
 	subscriptions  []chan proto.ReceivedMessage
 	port           int
 	stopping       int32
-	skipHandshake  bool
 }
 
 func (c *commImpl) createConnection(endpoint string, expectedPKIID common.PKIidType) (*connection, error) {

gossip/comm/comm_test.go

@@ -112,7 +112,6 @@ func newCommInstance(port int, sec api.MessageCryptoService) (Comm, error) {
 }
 
 type msgMutator func(*proto.SignedGossipMessage) *proto.SignedGossipMessage
-type msgConsumer func(*proto.SignedGossipMessage)
 
 type tlsType int
 
@@ -221,6 +220,7 @@ func TestHandshake(t *testing.T) {
 
 	// Positive path 1 - check authentication without TLS
 	ll, err := net.Listen("tcp", fmt.Sprintf("%s:%d", "", 9611))
+	assert.NoError(t, err)
 	s := grpc.NewServer()
 	go s.Serve(ll)