Redirect uses site_offline variable which isnt used by Drupal 7 anymore

I ran into the issue that Redirect doesnt work completely, after short research I found that the failing code was this one:

function redirect_can_redirect() {
  /* ...  */
    elseif (variable_get('site_offline', 0) || defined('MAINTENANCE_MODE')) {
      // Do not redirect in offline or maintenance mode.
      $can_redirect = FALSE;
    }
  /* ...  */
  return $can_redirect;
}

The bug resides in the usage of the site_offline setting which was migrated to maintenance_mode in Drupal 7 (see update.inc).

function update_fix_d7_requirements() {
    /* ...  */
    // Old variable is removed in update for system.module, see
    // system_update_7069().
    $site_offline = variable_get('site_offline', -1);
    if ($site_offline != -1) {
      variable_set('maintenance_mode', $site_offline);
    }
    /* ...  */
}

I don't know why but I have site_offline set to 1 in my install which broke redirect module to work, however the rest of the site was unaffected.