Remove DNS code from the main repo (code is now in http://github.com/kubernetes/dns)

hack/.linted_packages

@@ -15,7 +15,6 @@ cmd/kube-apiserver/app/options
 cmd/kube-controller-manager
 cmd/kube-controller-manager/app/options
 cmd/kube-discovery
-cmd/kube-dns
 cmd/kube-proxy
 cmd/kubeadm
 cmd/kubeadm

hack/lib/golang.sh

@@ -23,7 +23,6 @@ readonly KUBE_GOPATH="${KUBE_OUTPUT}/go"
 # kube::build::source_targets in build/common.sh as well.
 kube::golang::server_targets() {
   local targets=(
-    cmd/kube-dns
     cmd/kube-proxy
     cmd/kube-apiserver
     cmd/kube-controller-manager