fix install.py for windows (#5918)
fix install.py for windows (#5918)


jpallas/beakerx,twosigma/beaker-notebook,jpallas/beakerx,jpallas/beakerx,twosigma/beaker-notebook,jpallas/beakerx,twosigma/beakerx,jpallas/beakerx,twosigma/beakerx,twosigma/beaker-notebook,twosigma/beakerx,twosigma/beakerx,twosigma/beakerx,twosigma/beakerx,twosigma/beaker-notebook,jpallas/beakerx,twosigma/beaker-notebook