sched: Improve logging if KIST is disabled

      goto end;

    case SCHEDULER_KIST:

      if (!scheduler_can_use_kist()) {

        log_warn(LD_SCHED, "Scheduler KIST can't be used. Consider removing "

                           "it from Schedulers or if you have a tor built "

                           "with KIST support, you should make sure "

                           "KISTSchedRunInterval is a non zero value");

#ifdef HAVE_KIST_SUPPORT

        if (get_options()->KISTSchedRunInterval == -1) {

          log_info(LD_SCHED, "Scheduler type KIST can not be used. It is "

                             "disabled because KISTSchedRunInterval=-1");

        } else {

          log_notice(LD_SCHED, "Scheduler type KIST has been disabled by "

                               "the consensus.");

        }

#else /* HAVE_KIST_SUPPORT */

        log_info(LD_SCHED, "Scheduler type KIST not built in");

#endif /* HAVE_KIST_SUPPORT */

        continue;

      }

      the_scheduler = get_kist_scheduler();