Allow factory install shim to be overlay installed

src/platform/factory_installer/factory_install.sh

 #!/bin/sh -e
 
 # 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.
 
 . "$(dirname "$0")/chromeos-common.sh"
 . "/opt/google/memento_updater/memento_updater_logging.sh"
 
 if [ $(id -u) -ne 0 ]; then
   echo "You must run this as root."
   exit 1
 fi
 
-# If we get in a respawn loop, sleeping for 1 minute before starting is nice.
-sleep 60
-
 # TODO(adlr): pick an install device in a matter that works on x86 and ARM.
 # This works on x86 only, afaik.
 DST=/dev/sda
 DST_FACTORY_PART=3
 DST_RELEASE_PART=5
 DST_OEM_PART=8
 DST_STATE_PART=1
 
 log "Factory Install: Setting partition table"
 
@@ skipping 32 matching lines @@
   if [ "$RESULT" != "UPDATED" ]; then
     log "Factory Install: AU failed"
     exit 1
   fi
 done
 
 log "All done installing."
 
 shutdown -r now
 sleep 1d  # sleep indefinitely to avoid respawning rather than shutting down