Fix possible incremental build issue

We tried to start using toybox's sed, but it produced invalid results
with one of init's genrules. Clear out that generated code to fix future
incremental builds, since we don't rebuild everything on a $PATH change.

Bug: 122744241
Test: generate bad file, remove toybox sed, apply this change
Change-Id: I197aa4b68b2fe309b3033e8736e1d80c8ded80ad
diff --git a/CleanSpec.mk b/CleanSpec.mk
index b32868e..8a28303 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -532,6 +532,9 @@
 # Remove obsolete apps
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 
+# Remove corrupt generated rule due to using toybox's sed
+$(call add-clean-step, rm -rf $(SOONG_OUT_DIR)/.intermediates/system/core/init/generated_stub_builtin_function_map)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************