Fix issue #12939338: Android version showing as 'KKWT'

Thou shalt be...  L!

Change-Id: I53e66eaf64183fbab0b1035cdb376b25abab4879
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 488014b..4eec704 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -229,6 +229,11 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
+# L development
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************