Simple workaround for this bug: 1) Create the venv with --without-pip. For instance:
/usr/bin/python3.5 -m venv --without-pip <venv-dir>
2) Download https://bootstrap.pypa.io/get-pip.py as ~/tmp/get-pip.py.
3) Bootstrap pip "manually" in your venv:
<venv-dir>/bin/python ~/tmp/get-pip.py
HTH
--
Florent

