Add func/unit tests for the engulfment process

[jschmid1]

After repeatingly hitting bugs in that area, we should make sure to avoid that in the future by adding tests.

See: https://trello.com/c/7uu9MgNa/32-add-unit-func-tests-for-the-engulfment-process

[jschmid1]

Add unit/func tests for the engulfment process

[smithfarm]

This means we need an integration test that deploys SES4 with ceph-deploy.

[jschmid1]

This means we need an integration test that deploys SES4 with ceph-deploy.

right

[tserong]

I've got most of an initial baseline engulf test in https://github.com/SUSE/DeepSea/pull/1387. It'll engulf the current cluster and make sure it's the same as what was originally deployed. I know that's not the same as engulfing an old version, but it will (very importantly) let us know if changes to other areas of deepsea break the engulf in general; while working on that test, I already found a couple of small regressions, which are also fixed in #1387. For complete upgrade/engulf testing though, we'll need scaffolding outside DeepSea to do the SES4+ceph-deploy thing.