Update: I fixed this by manually switching branch for magnumclient repo to stable/pike and running sudo python setup.py install. IMHO it should be done by devstack or magnum (both were pinned to stable/pike).
Update: I fixed this by manually switching branch for magnumclient repo to stable/pike and running sudo python setup.py install. IMHO it should be done by devstack or magnum (both were pinned to stable/pike).