vendor: Remove reference to github.com/juju/ratelimit
It isn't being used or vendored
@@ -29,7 +29,6 @@ github.com/vishvananda/netlink master
github.com/vishvananda/netns master
github.com/opencontainers/image-spec v1.0.0
github.com/opencontainers/runtime-spec v1.0.0
-github.com/juju/ratelimit 5b9ff866471762aa2ab2dced63c9fb6f53921342
github.com/tchap/go-patricia v2.2.6
gopkg.in/cheggaaa/pb.v1 v1.0.7
gopkg.in/inf.v0 v0.9.0
