make sure non-image-changing upgrades work

[joel-bluedata]

Part of issue https://github.com/bluek8s/kubedirector/issues/588 ; related to issue #617.

It's quite possible that an upgrade will change some things about the kdapp (including the config package) but NOT change the container image. In which case KD may have things it needs to do to the container (e.g. issue #617 for config package changes) and we need to make sure that it is not completely relying on container-image-change as an indicator of an upgrade.