Add a CleanSpec for bootable/recovery

Change-Id: Ifa7a3aa5e2e3fd5d13266115d592bbfd0aa309c5
diff --git a/CleanSpec.mk b/CleanSpec.mk
index b84e1b6..ecf89ae 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -47,3 +47,4 @@
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/EXECUTABLES/recovery_intermediates)