Gate 2.7 (centos7.x) six is really way to old

[Joshua Harlow]

This is causing the rpmbuild of python cryptography to fail:

'''
Installed /home/jenkins/workspace/gate-anvil-rpms-dsvm-devstack-centos7/openstack/deps/rpmbuild/python-cryptography-0.9.3-0.el7.centos.src.rpm/BUILD/cryptography-0.9.3/.eggs/enum34-1.0.4-py2.7.egg
Traceback (most recent call last):
  File "setup.py", line 342, in <module>
    **keywords_with_side_effects(sys.argv)
  File "/usr/lib64/python2.7/distutils/core.py", line 112, in setup
    _setup_distribution = dist = klass(attrs)
  File "/usr/lib/python2.7/site-packages/setuptools/dist.py", line 268, in __init__
    self.fetch_build_eggs(attrs['setup_requires'])
  File "/usr/lib/python2.7/site-packages/setuptools/dist.py", line 313, in fetch_build_eggs
    replace_conflicting=True,
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 836, in resolve
    dist = best[req.key] = env.best_match(req, ws, installer)
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 1074, in best_match
    dist = working_set.find(req)
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 711, in find
    raise VersionConflict(dist, req)
pkg_resources.VersionConflict: (six 1.3.0 (/usr/lib/python2.7/site-packages), Requirement.parse('six>=1.4.1'))
error: Bad exit status from /var/tmp/rpm-tmp.IyDOhl (%build)
'''

http://logs.openstack.org/57/207657/4/check/gate-anvil-rpms-dsvm-devstack-centos7/32e1285/output/rpmbuild-python-cryptography-0.9.3-0.el7.centos.src.rpm.log