Update deployment status after upgrade converge
Update deployment status after upgrade converge

Now that UpgradeConverge inherits from UpgradePrepare, overcloud
status is left as 'DEPLOYING' after it finishes. Let's set the
status to 'DEPLOY_SUCCESS'.

Note: With ephemeral heat (Wallaby and after) we would not need the
converge step as there is no stack/plan. This change would be
backported to stable/train.

Change-Id: I4329b21adbc4cd568c0a164d2778b79df700ae48

openstack/python-tripleoclient