Unfortunately the fix is not yet backported to vivid or wily. To fix it yourselves you need to remove argparse from the following file:
vivid: /usr/lib/python3/dist-packages/stevedore-1.3.0.egg-info/requires.txt wily: /usr/lib/python3/dist-packages/stevedore-1.5.0.egg-info/requires.txt
Unfortunately the fix is not yet backported to vivid or wily. To fix it yourselves you need to remove argparse from the following file:
vivid: /usr/lib/ python3/ dist-packages/ stevedore- 1.3.0.egg- info/requires. txt python3/ dist-packages/ stevedore- 1.5.0.egg- info/requires. txt
wily: /usr/lib/