amends b27ba5a of #2602 so that the disposal of `h2o_req_t` would be delayed only when the caller is the generator
amends b27ba5a of #2602 so that the disposal of `h2o_req_t` would be delayed only when the caller is the generator

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