Remove or update the corresponding CI jobs. Use the new custom Cirros
image in the HTTP job to avoid relying on CentOS.
Temporary increase complexity requirements while we have a deprecation
warning in the provisioner.
Change-Id: I5e65f9949ee3b78430309017800b88c1ba21dd02
Also limit lower-constraints to only direct dependencies, otherwise
things conflict with each other (and of little use anyway).
Change-Id: Ice8b6a72f5833d625352ffd09f64608afc4eac67