Currently the online database column is not considered when displaying
the "baremetal conductor list" Alive status. This means that when a
conductor is stopped gracefully it will be shown as (inaccurately)
alive for the duration of [conductor]graceful_timeout.
This change adds the online field to the alive evaluation, so the
conductor must be online *and* have a recent heartbeat.
Change-Id: Ic5a8d56ec236faca1b9797bd0d3e42c956469fab