travis: a_download_only_test: GetKubeadmCachedBinaries not declared by package constant

[tstromberg]

test/integration/a_download_only_test.go:68:35: GetKubeadmCachedBinaries not declared by package constants (typecheck)

				for _, bin := range constants.GetKubeadmCachedBinaries() {

[afbjorklund]

I guess you know this, but it was deleted in 2f1a11d

-// GetKubeadmCachedBinaries gets the binaries to cache for kubeadm
-func GetKubeadmCachedBinaries() []string {
-       return []string{"kubelet", "kubeadm"}
-}
+// KubeadmBinaries are Kubernetes release binaries required for kubeadm
+var KubeadmBinaries = []string{"kubelet", "kubeadm"}