h2olog: remove "const" for move semantics (thanks to @syohex)
h2olog: remove "const" for move semantics (thanks to @syohex)

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