Move up to API 21, Lollipop MR1.

Change-Id: I81c3455d99673447ac0bc1b48d5ab1500b2bfd20
diff --git a/CleanSpec.mk b/CleanSpec.mk
index f348692..a4a44ca 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -299,6 +299,11 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
+# API 22!
+$(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
 # ************************************************