It seems we want to output stack events irrespective of verbosity,
as per https://review.opendev.org/#/c/724856/. There is no point of
having all the useless logic for verbosity in wait_for_stack_ready().
Also fixes stack update for scale-down to list events.
Change-Id: I96a2a2255253aa2feac62b67ad5d5813e3126a20