[VOL-4290] Voltha go library updates for gRPC migration

Change-Id: I1aa2774beb6b7ed7419bc45aeb53fcae8a8ecda0
diff --git a/vendor/go.etcd.io/etcd/clientv3/txn.go b/vendor/go.etcd.io/etcd/clientv3/txn.go
index c19715d..c3c2d24 100644
--- a/vendor/go.etcd.io/etcd/clientv3/txn.go
+++ b/vendor/go.etcd.io/etcd/clientv3/txn.go
@@ -18,7 +18,7 @@
 	"context"
 	"sync"
 
-	pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 
 	"google.golang.org/grpc"
 )