greenfield install error

[Robert Collins]

https://jenkins04.openstack.org/job/gate-oslo.config-python26/141/console

testtools requires unittest2 and extras
extras requires testtools for testtools.TestCommand

If pip decides to install extras before unittest2, then extras will fail to install because:
2015-03-09 23:40:27.595 | Running setup.py install for extras
2015-03-09 23:40:27.595 | Traceback (most recent call last):
2015-03-09 23:40:27.595 | File "<string>", line 1, in <module>
2015-03-09 23:40:27.595 | File "/home/jenkins/workspace/gate-oslo.config-python26/.tox/py26/build/extras/setup.py", line 8, in <module>
2015-03-09 23:40:27.595 | testtools_cmd = extras.try_import('testtools.TestCommand')
2015-03-09 23:40:27.595 | File "extras/__init__.py", line 46, in try_import
2015-03-09 23:40:27.595 | module = __import__(module_name)
2015-03-09 23:40:27.595 | File "/home/jenkins/workspace/gate-oslo.config-python26/.tox/py26/lib/python2.6/site-packages/testtools/__init__.py", line 109, in <module>
2015-03-09 23:40:27.595 | from testtools.distutilscmd import (
2015-03-09 23:40:27.595 | File "/home/jenkins/workspace/gate-oslo.config-python26/.tox/py26/lib/python2.6/site-packages/testtools/distutilscmd.py", line 10, in <module>
2015-03-09 23:40:27.595 | from testtools.run import TestProgram, TestToolsTestRunner
2015-03-09 23:40:27.596 | File "/home/jenkins/workspace/gate-oslo.config-python26/.tox/py26/lib/python2.6/site-packages/testtools/run.py", line 28, in <module>
2015-03-09 23:40:27.596 | discover_impl = unittest.loader
2015-03-09 23:40:27.596 | AttributeError: 'module' object has no attribute 'loader'