Increase open files limit for XGBoost stress test to 150
Increase open files limit for XGBoost stress test to 150

100 seems too low after recent changes; no sign of a leak

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