[FAB-11996] Enable creation of raft based channels

This commit enables creation of Raft based channel and aligns unit-tests
accordingly.

Change-Id: Iead5cddcab5137b0bce9740f47db8a3f583f2f4f
Signed-off-by: Artem Barger <bartem@il.ibm.com>

orderer/consensus/etcdraft/chain.go

@@ -150,7 +150,7 @@ func (c *Chain) checkConfigUpdateValidity(ctx *common.Envelope) error {
 
 	switch chdr.Type {
 	case int32(common.HeaderType_ORDERER_TRANSACTION):
-		return errors.Errorf("channel creation requests not supported yet")
+		return nil
 	case int32(common.HeaderType_CONFIG):
 		configEnv, err := configtx.UnmarshalConfigEnvelope(payload.Data)
 		if err != nil {

orderer/consensus/etcdraft/chain_test.go

@@ -474,9 +474,9 @@ var _ = Describe("Chain", func() {
 							configSeq = 0
 						}) // BeforeEach block
 
-						It("should throw an error", func() {
+						It("should be able to create a channel", func() {
 							err := chain.Configure(configEnv, configSeq)
-							Expect(err).To(MatchError("channel creation requests not supported yet"))
+							Expect(err).NotTo(HaveOccurred())
 						})
 					})
 				}) // Context block for type A config