Try to work around PyPy 3 install failure [1] based on [2]
Try to work around PyPy 3 install failure [1] based on [2]

[1] https://travis-ci.org/github/paylogic/py2deb/jobs/714415991#L714
[2] https://stackoverflow.com/questions/47011935/indexerror-list-index-out-of-range-using-pip

paylogic/py2deb,paylogic/py2deb