close the connection when upstream closes, only when the connection is acting as a tunnel (partially reverts 4ee4282 that changed the behavior for ordinary request-response cycle)
close the connection when upstream closes, only when the connection is acting as a tunnel (partially reverts 4ee4282 that changed the behavior for ordinary request-response cycle)

devnexen/h2o,cwyang/h2o,yannick/h2o,yannick/h2o,devnexen/h2o,devnexen/h2o,devnexen/h2o,yannick/h2o,yannick/h2o,devnexen/h2o,cwyang/h2o,h2o/h2o,h2o/h2o,cwyang/h2o,h2o/h2o,h2o/h2o,h2o/h2o,yannick/h2o,h2o/h2o,h2o/h2o,devnexen/h2o,yannick/h2o,devnexen/h2o,h2o/h2o,h2o/h2o,cwyang/h2o,yannick/h2o,cwyang/h2o,cwyang/h2o,yannick/h2o,devnexen/h2o,cwyang/h2o,yannick/h2o,cwyang/h2o,devnexen/h2o