Fixes a regression introduced in d1b5681ba0.

Looks like `.finished` is a property on the main object, not on some
`.async_result` object.

We were previously trying to reach into `.rc`,
but there's no such thing if `async_result.finished == 0`.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2153

One that doesn't trip up ansible-lint, causing `load-failure` errors.

Reference: https://ansible-lint.readthedocs.io/en/latest/default_rules/#no-changed-when

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1939