A good workaround for these kind of setuptools/buildout bootstrapping issues is to avoid the old-style bootstrap and use pip to install both setuptools and zc.buildout. Like:
virtualenv --clear -p python2.7 .
bin/pip install -r requirements.txt
Where the requirements.txt is like below, and you make sure your buildout version pins for setuptools and zc.buildout are identical to the versions selected for pip.