def list_request_path(marker, prefix, details, limit)
      query_string = "limit=#{limit}"
      query_string += "&marker=#{Raca::Util.url_encode(marker)}" if marker
      query_string += "&prefix=#{Raca::Util.url_encode(prefix)}" if prefix
      query_string += "&format=json"      if details
      container_path + "?#{query_string}"
    end
def list_request_path(marker, prefix, details, limit)
      query_string = "limit=#{limit}"
      query_string += "&marker=#{Raca::Util.url_encode(marker)}" if marker
      query_string += "&prefix=#{Raca::Util.url_encode(prefix)}" if prefix
      query_string += "&format=json"      if details
      container_path + "?#{query_string}"
    end
build the request path for listing the contents of a container