Remove /vendor/default.prop

Contents that were in /vendor/default.prop are now in /vendor/build.prop

The content is placed at the top of build.prop to keep the existing
order between default.prop and builld.prop.

Bug: 117892318
Test: TH passes
Test: inspect  /vendor/build.prop and check if it has contents from
the old /vendor/default.prop file

Change-Id: Ifa1f1dca3b4f4a5fa87d26b8ee058ee706dc54bb
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 97dc31f..15fb58d 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -722,6 +722,8 @@
 $(call add-clean-step, rm -rf $(HOST_OUT)/vts/*)
 $(call add-clean-step, rm -rf $(HOST_OUT)/framework/vts-tradefed.jar)
 
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/vendor/default.prop)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************