I think, in this script, it is a mute point:  the script sets PYTHON_HOME, and uses your existing WORKON_HOME if set (so old way is fine).  **And** the script sets up WORKON_HOME for it's internal use already - i.e., use it; don't override it with hardcoded values. 

This change just updates so that if user doesn't have / use WORKON_HOME, then what the script creates will match the current docs [http://virtualenvwrapper.readthedocs.org/]