Add support to sign boot images with vboot.

Change-Id: I924468fe06f7d38d4fc49c2ae9dfee734fd58867
Signed-off-by: David Riley <davidriley@google.com>
(cherry picked from commit 14fb7236c1942a9f5050b3e608a0f5f4cd1cae1d)
diff --git a/core/product.mk b/core/product.mk
index d3df582..77e053f 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -97,10 +97,12 @@
     PRODUCT_RESTRICT_VENDOR_FILES \
     PRODUCT_VENDOR_KERNEL_HEADERS \
     PRODUCT_BOOT_JARS \
+    PRODUCT_SUPPORTS_VBOOT \
     PRODUCT_SUPPORTS_VERITY \
     PRODUCT_OEM_PROPERTIES \
     PRODUCT_SYSTEM_PROPERTY_BLACKLIST \
     PRODUCT_SYSTEM_SERVER_JARS \
+    PRODUCT_VBOOT_SIGNING_KEY \
     PRODUCT_VERITY_SIGNING_KEY \
     PRODUCT_SYSTEM_VERITY_PARTITION \
     PRODUCT_VENDOR_VERITY_PARTITION \