test: fix post rewrite hook report

First expected, then actual.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5407-post-rewrite-hook.sh

@@ -31,8 +31,8 @@ clear_hook_input () {
 }
 
 verify_hook_input () {
-	test_cmp "$TRASH_DIRECTORY"/post-rewrite.args expected.args &&
-	test_cmp "$TRASH_DIRECTORY"/post-rewrite.data expected.data
+	test_cmp expected.args "$TRASH_DIRECTORY"/post-rewrite.args &&
+	test_cmp expected.data "$TRASH_DIRECTORY"/post-rewrite.data
 }
 
 test_expect_success 'git commit --amend' '