cleanbuild: add *.zip.sha256sum to installclean_files

Change-Id: I91f92349423eeb99e7e4521f6239baabe8b1314c
diff --git a/ui/build/cleanbuild.go b/ui/build/cleanbuild.go
index 41cb5ab..251c955 100644
--- a/ui/build/cleanbuild.go
+++ b/ui/build/cleanbuild.go
@@ -125,6 +125,7 @@
 		hostCommonOut("obj/PACKAGING"),
 		productOut("*.img"),
 		productOut("*.zip"),
+		productOut("*.zip.sha256sum"),
 		productOut("android-info.txt"),
 		productOut("misc_info.txt"),
 		productOut("apex"),