pypa/virtualenv — pull request #645 by tzulberti (2014-09-10 14:58:26+00:00)
Title: Solved problem when using "set -u" in bash

If you use "set -u" in bash, before the activation of an virtualenv
then, the activation will fail because there are some variables
that are unbond

The same happens if the virtualenv is active and you want to
deactivate it.