Make the packaging of VBOOT_SIGNER tools conditional. am: 5e04c38bbd am: 36846f0b53 am: 9084561e77 am: 4565da53fc am: 8ed9cded69 am: 0c518253ac
am: 006db5f1f1

Change-Id: If254fc84fc00c5d3fe7c93cc62b984d1618acbb0