Actually update binaries during kube-push

This was a dumb mistake during a re-factor of configure-vm. I tested
this early, re-factored the tail of this file, spot checked kube-push
and failed to test kube-push properly. My bad.

Fixes #5361. Fixes #5408.

cluster/gce/configure-vm.sh

@@ -360,6 +360,7 @@ else
   ensure-install-dir
   set-kube-env
   create-salt-pillar
+  download-release
   run-salt
   echo "== kube-push node config done =="
 fi