Robustify starting of ssh connection to vm updater.

bin/cros_run_vm_update

 #!/bin/bash
 
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # Updates an existing vm image with another image.
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
 # Load common CrOS utilities.  Inside the chroot this file is installed in
@@ skipping 32 matching lines @@
 
 # Parse command line.
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
 
 [ -n "${FLAGS_vm_image_path}" ] || \
   die "You must specify a path to a vm image."
 
 trap stop_kvm EXIT
 start_kvm "${FLAGS_vm_image_path}"
+retry_until_ssh
 
 if [ -n "${FLAGS_update_image_path}" ]; then
   IMAGE_ARGS="--image=$(readlink -f ${FLAGS_update_image_path})"
 fi
 
 if [ -n "${FLAGS_payload}" ]; then
   IMAGE_ARGS="--payload=${FLAGS_payload}"
 fi
 
 if [ -n "${FLAGS_proxy_port}" ]; then
   IMAGE_ARGS="${IMAGE_ARGS} --proxy_port=${FLAGS_proxy_port}"
 fi
 
 "${SCRIPTS_DIR}/image_to_live.sh" \
   --for_vm \
   --remote=127.0.0.1 \
   --ssh_port=${FLAGS_ssh_port} \
   --stateful_update_flag=${FLAGS_stateful_update_flag} \
   --src_image="${FLAGS_src_image}" \
   --update_url="${FLAGS_update_url}" \
   --verify \
   ${IMAGE_ARGS}