Add updatable_apex.mk

The product abstracts configs that need to be set to support updating of
APEXes.

Bug: 130418467
Test: m
Test: adb shell getprop ro.apex.updatable in Pixel 2 and 3
Test: adb shell /system/apex/com.android.apex.cts.shim.apex exists.
Change-Id: Id5aa944ceba6a6846308f1c18a08af8b3bb38589
diff --git a/device.mk b/device.mk
index 4415302..b175402 100755
--- a/device.mk
+++ b/device.mk
@@ -17,6 +17,9 @@
 # Installs gsi keys into ramdisk, to boot a GSI with verified boot.
 $(call inherit-product, $(SRC_TARGET_DIR)/product/gsi_keys.mk)
 
+# Enable updating of APEXes
+$(call inherit-product, $(SRC_TARGET_DIR)/product/updatable_apex.mk)
+
 ifneq (,$(filter 27, $(PRODUCT_EXTRA_VNDK_VERSIONS)))
     _vndk_test := true
 endif
@@ -733,9 +736,6 @@
 PRODUCT_PROPERTY_OVERRIDES += \
     debug.sf.early_gl_app_phase_offset_ns=15000000
 
-PRODUCT_PROPERTY_OVERRIDES += \
-    ro.apex.updatable=true
-
 # Use /product/etc/fstab.postinstall to mount system_other.
 PRODUCT_PRODUCT_PROPERTIES += \
     ro.postinstall.fstab.prefix=/product