Install Updater as a system privileged app

Ensure backward compatibility with previous release where Updater
was built in the tree, and thus ended up installed in
`/system/priv-app`.

FPIIM-742

Change-Id: I501b5ef023d55c2be3a026b18ea9bb3914528126
diff --git a/Android.mk b/Android.mk
index 81191ce..197d4dd 100644
--- a/Android.mk
+++ b/Android.mk
@@ -11,5 +11,6 @@
 LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
 LOCAL_CERTIFICATE := PRESIGNED
 LOCAL_SRC_FILES := prebuilts/apk/com.fairphone.updater.apk
+LOCAL_MODULE_PATH := $(PRODUCT_OUT)/system/priv-app
 
 include $(BUILD_PREBUILT)