Rewrite test_restore to delete setuptools to break test virtualenv
Rewrite test_restore to delete setuptools to break test virtualenv

Previoulsy, test_restore test relied on breaking the test virtualenv by
removing the site.py from the test virtualenv.

Since virtualenv 20+ doesn't inject its own site.py when creating a
Python 3 virtualenv anymore, reling on removing the site.py from the
testing virtualenv no longer works.

Deleting everything related to setuptools seems like a good way to break
the 'import setuptools' statement.

berdario/pew,berdario/pew