Log kubelet /healthz failure reasons to supervisord log file

cluster/saltbase/salt/supervisor/kubelet-checker.sh

@@ -34,6 +34,7 @@ max_seconds=10
 while true; do
   if ! curl --insecure -m ${max_seconds} -f -s https://127.0.0.1:{{kubelet_port}}/healthz > /dev/null; then
     echo "kubelet failed!"
+    curl --insecure -s http://127.0.0.1:{{kubelet_port}}/healthz
     exit 2
   fi
   sleep 10