There was a non-obvious dependency from the AccountDeactivator task to
the auth.autoUpdateAccountActiveStatus. A properly configured account
deactivator task wouldn't be scheduled if the
autoUpdateAccountActiveStatus was set to false and the reason wasn't
obvious to a Gerrit admin.
Also log a warning if the account deactivation task is configured but
will not be scheduled.
Change-Id: Icf13c1b306c52c815438c01d23aa38df0ba30793
f0966117b0