def delete(nsc, site_id)
      uri = "/api/2.1/site_configurations/#{site_id}/alerts/#{id}"
      AJAX.delete(nsc, uri, AJAX::CONTENT_TYPE::JSON)
    end
def delete(nsc, site_id)
      uri = "/api/2.1/site_configurations/#{site_id}/alerts/#{id}"
      AJAX.delete(nsc, uri, AJAX::CONTENT_TYPE::JSON)
    end
delete an alert from the given site