updater_sample: Build SystemUpdaterSample as non-privileged app by default.

Prior to the change, SystemUpdaterSample was built as privileged app.
It must be installed along with the matching privapp-permissions
whitelist change (as noted in updater_sample/README.md), otherwise would
block device booting if installed unintentionally (e.g. with `mm` or
`mmma`).

This CL avoids putting the device in a bad state due to a sample app.

Fixes: 135703777
Test: `lunch aosp_taimen-userdebug && m -j installclean &&
          mmma -j bootable/recovery && m -j`
      Flash on device and boot successfully.
Test: Run the tests per instructions in updater_sample/README.md.
Change-Id: Ib8b587c77570f05f7db748fad84744fa45016aab
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 6bd1eb1..8405d20 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -55,6 +55,9 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/data/nativetest64/recovery_component_test)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/testcases/recovery_component_test)
 
+$(call add-clean-step, find $(OUT_DIR) -type f -name "SystemUpdaterSample*" -print0 | xargs -0 rm -f)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/priv-app/SystemUpdaterSample)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************