hack to deal with non-enum col having nan in vec.min() or vec.max()..algo needs min 2 deep histogram (max_qbins+1) ..code was creating a 1 deep for the special case of nans in vec.min(). kind of ugly (exec was creating an empty key and causing the issue) ..but it seems to work
Merge branch 'master' of https://github.com/0xdata/h2o