Backspace should perform delete on console.

  commit 2c0cc66976f5e4d77982a0bc256ab9c7e5efba4e
  Author: Alexander Eremin <a.eremin@nexenta.com>
  Date:   Wed Oct 5 14:13:10 2011 +0000

      Re #6790 backspace should perform delete on console
Remove etc/release from overlay directory. It is generated dynamically at image creation time.
EC overlay manifest adjustments
Remove upload_image script