fast-export: fix comparison in tests

First the expected, then the actual, otherwise the diff would be the
opposite of what we want.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9350-fast-export.sh

@@ -303,7 +303,7 @@ test_expect_success 'dropping tag of filtered out object' '
 (
 	cd limit-by-paths &&
 	git fast-export --tag-of-filtered-object=drop mytag -- there > output &&
-	test_cmp output expected
+	test_cmp expected output
 )
 '
 
@@ -320,7 +320,7 @@ test_expect_success 'rewriting tag of filtered out object' '
 (
 	cd limit-by-paths &&
 	git fast-export --tag-of-filtered-object=rewrite mytag -- there > output &&
-	test_cmp output expected
+	test_cmp expected output
 )
 '
 
@@ -351,7 +351,7 @@ test_expect_failure 'no exact-ref revisions included' '
 	(
 		cd limit-by-paths &&
 		git fast-export master~2..master~1 > output &&
-		test_cmp output expected
+		test_cmp expected output
 	)
 '