fixup! builtin/gc: fix crash when running git maintenance start

Author: derrickstolee

t/t7900-maintenance.sh

@@ -652,11 +652,12 @@ test_expect_success 'start without GIT_TEST_MAINT_SCHEDULER' '
 	write_script script/crontab <<-EOF &&
 	echo "\$*" >>"$(pwd)"/crontab.log
 	EOF
+	PATHADD="$(pwd)/script" &&
 	git init repo &&
 	(
 		cd repo &&
 		sane_unset GIT_TEST_MAINT_SCHEDULER &&
-		PATH="$(pwd)/../script:$PATH" git maintenance start --scheduler=crontab
+		PATH="$PATHADD:$PATH" git maintenance start --scheduler=crontab
 	) &&
 	test_grep -- -l crontab.log &&
 	test_grep -- git_cron_edit_tmp crontab.log