Change name of overlay subdir property to sku.

Also move the SKU subdirectories directly under /vendor/overlay.

Bug: 31692079
Change-Id: I68c712b13918cc99629534580ee4f77d9e5b3823
diff --git a/libs/androidfw/AssetManager.cpp b/libs/androidfw/AssetManager.cpp
index 6fb57fa..daf3592 100644
--- a/libs/androidfw/AssetManager.cpp
+++ b/libs/androidfw/AssetManager.cpp
@@ -76,10 +76,9 @@
 const char* AssetManager::RESOURCES_FILENAME = "resources.arsc";
 const char* AssetManager::IDMAP_BIN = "/system/bin/idmap";
 const char* AssetManager::OVERLAY_DIR = "/vendor/overlay";
+const char* AssetManager::OVERLAY_SKU_DIR_PROPERTY = "ro.boot.vendor.overlay.sku";
 const char* AssetManager::TARGET_PACKAGE_NAME = "android";
 const char* AssetManager::TARGET_APK_PATH = "/system/framework/framework-res.apk";
-const char* AssetManager::OVERLAY_SUBDIR = "/system/vendor/overlay-subdir";
-const char* AssetManager::OVERLAY_SUBDIR_PROPERTY = "ro.boot.vendor.overlay.subdir";
 const char* AssetManager::IDMAP_DIR = "/data/resource-cache";
 
 namespace {