Add cliff, pycadf, stevedore, & taskflow from oslo

Oslo has adopted 4 libraries that were previously on
stackforge, so we can now install them from source.

Change-Id: I6b6e20a7884b47ade466fc38641a5ac1a5f3e146
Fix hook script for Ironic

cleanup_ironic should not be started on "unstack" phase,
otherwise API service not restarted because auth cache
directory removed.

Change-Id: I3da86b9fb8c3ce1185aff05df0fa83cf259708f4
Merge "Fix hook script for Ironic"
Merge "Add cliff, pycadf, stevedore, & taskflow from oslo"
Merge branch 'master' of https://github.com/openstack-dev/devstack