Fix loggging user after free
Fix loggging user after free

conn->sock->input can't be free'd before calling
`h2o_dispose_request(&conn->req);`, because `h2o_dispose_request` calls
the logging handlers, which in turn might log parts of the socket input
buffer.

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