Add ro.product.locale

This is a BCP-47 language tag representing the default locale for a
given device. Support for the earlier mechanism of supplying a language
and region via ro.product.locale.region/language has been removed. This
change also removes support for supplying these properties via
PRODUCT_ADDITIONAL_PROPERTY_OVERRIDES. Devices that need to override
this should either rearrange their PRODUCT_LANGUAGES or supply a custom
.prop file.

bug: 17691569

Change-Id: I00c74098542b49b9c514a6ca39ea8d08179546c1
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 52a1b1f..4591fb7 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -315,6 +315,10 @@
 # an ABI change since the names will mangle differently.
 $(call add-clean-step, rm -rf $(OUT_DIR))
 
+# Remove ro.product.locale.language/country and add ro.product.locale
+# instead.
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************