virtualenv confused about /usr/local/virtualenv vs /usr/virtualenv

[handrews]

The python virtual environment in the VM is at /usr/local/virtualenv, but some things seem to think that it is at /usr/virtualenv:

[vagrant@gcd-django-box /vagrant (master)]$ source /usr/local/virtualenv/bin/activate
(virtualenv)[vagrant@gcd-django-box /vagrant (master)]$ which pip
/usr/local/virtualenv/bin/pip
(virtualenv)[vagrant@gcd-django-box /vagrant (master)]$ pip --help
/usr/local/virtualenv/local/lib/python2.7/site-packages/pip/pep425tags.py:66: RuntimeWarning: invalid Python installation: unable to open /usr/virtualenv/lib/python2.7/config/Makefile (No such file or directory)
  warnings.warn("{0}".format(e), RuntimeWarning)

[regular pip --help output follows]

No /usr/virtualenv directory exists.

According to @grosenbaum
"""
Seems to be a problem with python package of Ubuntu (see pypa/pip#1074)

Simple solution, I suggest to move virtualenv from /usr/local to /opt.
"""

[grosenbaum]

Fix in #5