Use fsm->action to decide whether we need a backup or not.

Use fsm->action to decide whether we need a backup or not.

- We already have a carefully precalculated action decided for these
  things, use that instead of bunch of arbitrary (except for osuffix)
  conditions depending on several nasty hacks and hidden assumptions.
  Doing so fixes stuff, who would've thought of that?
- Adjust test-suite expectations