When provided with a wrong password `rabbitmqctl
authenticate_user` returns a non-zero exit code
(65). This seems to be unexpected by the module and
it fails when `update_password` is set to 'always'.
To mitigate this behavior we augment the `_exec`
method by adding a `check_rc` flag (which defaults
to `True`, hence it's backward-compatible) and
override it when we need it (in `check_password`
method to address #56164).