Allow to install os-ken from git repo

os-ken is used by neutron ML2/OVS agent.
We need to install os-ken from source to test os-ken changes
against neutron. We already have tempest-integrated-networking job
in os-ken repo but it turns out it consumes os-ken from PyPI :-(

Change-Id: Ibcff212591e9fed25f1316403627269d81455b09
3 files changed