Comment 2 for bug 1620932

In the the attached patch plans will now be updated when deploying if they already exist. However, i'd like to propose the following strategy.

1. If the plan exists, and isn't deployed, delete it and then create a new one.

This is going to be a very common case as we create a default plan called overcloud with the default templates. So anyone doing anything slightly custom or using the `openstack overcloud deploy --templates` CLI command will be updating an existing plan, and the first time it will never be deployed. Deleting it first wont lose anything and will be cleaner.

2. If the plan exists, and is deployed, updated.

If it has already been deployed, then update the plan. This is because we don't currently allow deleting a plan that is deployed.

3. If the plan doesn't exist, create it.

This will happen for new plan names or when a user manually removes the initial plan.