Predict the Python version based on $VIRTUAL_ENV...
Predict the Python version based on $VIRTUAL_ENV
Try to make prediction of the Python's site-package version used by
virtualenv. If predicted path doesn't exist, continue with previous
behaviour.
This can be useful while working with different Python versions in
virtual environments other than system-used (previously provided via
`sys.version_info`). Note that this *only* updates $PYTHONPATH, so
3rd-libraries installed in virtualenv will be avialable. However the
Python interpreter contiunues to be other than the bundled in the
virtualenv (see `init_virtualenv()` docstring).
