Garm no longer fails on startup if a pool manager cannot be started. It
will attempt to start the pool manager in the background. If it fails
due to an unauthorized error, it will sleep for 3 hours. It is unlikely
it will work a second time if credentials are not updated in the config
and garm is restarted, so no point in getting rate limited.
Signed-off-by: Gabriel Adrian Samfira <gsamfira@cloudbasesolutions.com>