[PUBDEV-7327][FollowUp] Remove code for external backend from H2O (#4374)
[PUBDEV-7327][FollowUp] Remove code for external backend from H2O (#4374)


h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,h2oai/h2o-3