http-backend test: make empty CONTENT_LENGTH test more realistic

This is a test of smart HTTP, so it should use the smart HTTP endpoints
(e.g. /info/refs?service=git-receive-pack), not dumb HTTP (HEAD).

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t5562-http-backend-content-length.sh b/t/t5562-http-backend-content-length.sh
index f94d01f..b24d8b0 100755
--- a/t/t5562-http-backend-content-length.sh
+++ b/t/t5562-http-backend-content-length.sh
@@ -155,8 +155,8 @@
 
 test_expect_success 'empty CONTENT_LENGTH' '
 	env \
-		QUERY_STRING=/repo.git/HEAD \
-		PATH_TRANSLATED="$PWD"/.git/HEAD \
+		QUERY_STRING="service=git-receive-pack" \
+		PATH_TRANSLATED="$PWD"/.git/info/refs \
 		GIT_HTTP_EXPORT_ALL=TRUE \
 		REQUEST_METHOD=GET \
 		CONTENT_LENGTH="" \