Separate boot and recovery image signing from dm-verity

Allow dm-verity to be enabled without boot and recovery images being
signed. This makes it possible to enable only dm-verity to detect
corruption without confusing bootloaders that do not understand signed
images.

Bug: 19985143
Change-Id: Ie52c6ff595faa7a5c1f1bc1b37f6899c4d0c7001
diff --git a/core/product.mk b/core/product.mk
index 77e053f..b7e1aa9 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -97,6 +97,7 @@
     PRODUCT_RESTRICT_VENDOR_FILES \
     PRODUCT_VENDOR_KERNEL_HEADERS \
     PRODUCT_BOOT_JARS \
+    PRODUCT_SUPPORTS_BOOT_SIGNER \
     PRODUCT_SUPPORTS_VBOOT \
     PRODUCT_SUPPORTS_VERITY \
     PRODUCT_OEM_PROPERTIES \