[FAB-2676] Use atomic create ledger from GB

Currently while peer joins the channel it provided the genesis block
which is used to generate the ledger and consequently being committed
into newly generated ledger. Currently the creation has been done in
two phases.

This commit switches the create ledger from the genesis block
functionality to use atomic function which creates ledger with already
committed block.

Change-Id: I8371f9ee8f026bd98194817b48d8118c4df08dd7
Signed-off-by: Artem Barger <bartem@il.ibm.com>

core/peer/peer.go

@@ -234,17 +234,13 @@ func CreateChainFromBlock(cb *common.Block) error {
 	if err != nil {
 		return err
 	}
-	var ledger ledger.PeerLedger
-	if ledger, err = createLedger(cid); err != nil {
-		return err
-	}
 
-	if err := ledger.Commit(cb); err != nil {
-		peerLogger.Errorf("Unable to get genesis block committed into the ledger, chainID %v", cid)
-		return err
+	var l ledger.PeerLedger
+	if l, err = ledgermgmt.CreateWithGenesisBlock(cb); err != nil {
+		return fmt.Errorf("Cannot create ledger from genesis block, due to %s", err)
 	}
 
-	return createChain(cid, ledger, cb)
+	return createChain(cid, l, cb)
 }
 
 // MockCreateChain used for creating a ledger for a chain for tests