This sets `$what_VERSION` and `$what_REPO` for runc, cni, containerd and
kubernetes based on vendor.conf, removing the need to duplicate things in
hack/versions.
With this `update_hack_versions` becomes redundant so remove it and both calls.
Since CONTAINERD_REPO is now unconditionally set we can also simplify the
fetching of vendor.conf in update-vendor.sh a bit, so do so. Further since
`*_REPO` are now unconditionally set we can support alternative clone paths for
all of these repos by adjusting checkout_repo to make the 3rd argument
non-optional and always passing it. Since `CRITOOL_VERSION` is not coming from
`vendor.conf` (since it is not used from Go code) we manually set
`CRITOOL_REPO` for consistency.
The final wrinkle is that `k8s.io/kubernetes` is has a Go specific redirect in
the form of HTML meta headers returned from https://k8s.io/kubernetes/?go-get=1
which point to the real repo to clone. Parsing that in shell is tricky so just
hardcode that.
Fixes#540.
Signed-off-by: Ian Campbell <ijc@docker.com>
