change default storage driver for redhat

Signed-off-by: Robert Rettig <robert.rettig@ndgit.com>

libmachine/provision/redhat.go

@@ -134,7 +134,7 @@ func (provisioner *RedHatProvisioner) Provision(swarmOptions swarm.Options, auth
 	swarmOptions.Env = engineOptions.Env
 
 	// set default storage driver for redhat
-	storageDriver, err := decideStorageDriver(provisioner, "devicemapper", engineOptions.StorageDriver)
+	storageDriver, err := decideStorageDriver(provisioner, "overlay2", engineOptions.StorageDriver)
 	if err != nil {
 		return err
 	}

libmachine/provision/redhat_test.go

@@ -14,7 +14,7 @@ func TestRedHatDefaultStorageDriver(t *testing.T) {
 	p := NewRedHatProvisioner("", &fakedriver.Driver{})
 	p.SSHCommander = provisiontest.NewFakeSSHCommander(provisiontest.FakeSSHCommanderOptions{})
 	p.Provision(swarm.Options{}, auth.Options{}, engine.Options{})
-	if p.EngineOptions.StorageDriver != "devicemapper" {
-		t.Fatal("Default storage driver should be devicemapper")
+	if p.EngineOptions.StorageDriver != "overlay2" {
+		t.Fatal("Default storage driver should be overlay2")
 	}
 }