docker: revert shellcheck fix (#6288)

docker/runtime/backup-rotator.sh

@@ -21,7 +21,8 @@ main() {
 		exit 1
 	fi
 
-	find "${BACKUP_PATH}/" -type f -name "gogs-backup-*.zip" "-${FIND_EXPRESSION}" -print -exec rm "{}" +
+	# shellcheck disable=SC2086
+	find "${BACKUP_PATH}/" -type f -name "gogs-backup-*.zip" -${FIND_EXPRESSION} -print -exec rm "{}" +
 }
 
 main "$@"