[Updater] Preserve CleanSpec.mk

Test: update guice
Change-Id: I5e87db69ae8f310b1b00fa59a07bce22c0209edd
diff --git a/update_package.sh b/update_package.sh
index 0a854a7..8d5e3c6 100644
--- a/update_package.sh
+++ b/update_package.sh
@@ -34,6 +34,7 @@
 echo "Copying preserved files..."
 CopyIfPresent "Android.bp"
 CopyIfPresent "Android.mk"
+CopyIfPresent "CleanSpec.mk"
 CopyIfPresent "LICENSE"
 CopyIfPresent "NOTICE"
 cp -a -f -n $external_dir/MODULE_LICENSE_* .