fix TestGroFileEngine for CI
fix TestGroFileEngine for CI

dwhswenson/openpathsampling,dwhswenson/openpathsampling,openpathsampling/openpathsampling,choderalab/openpathsampling,openpathsampling/openpathsampling,dwhswenson/openpathsampling,openpathsampling/openpathsampling,openpathsampling/openpathsampling,choderalab/openpathsampling,dwhswenson/openpathsampling,choderalab/openpathsampling