http-push: clean up loose request when falling back to packed

In http-push's finish_request(), if we fail a loose object request we
may fall back to trying a packed request. But if we do so, we leave the
http_loose_object_request in place, leaking it.

We can fix this by always cleaning it up. Note that the obj_req pointer
here (which we'll set to NULL) is a copy of the request->userData
pointer, which will now point to freed memory. But that's OK. We'll
either release the parent request struct entirely, or we'll convert it
into a packed request, which will overwrite userData itself.

This leak is found by t5540, but it's not quite leak-free yet.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http-push.c

@@ -582,9 +582,10 @@ static void finish_request(struct transfer_request *request)
 			if (obj_req->rename == 0)
 				request->obj->flags |= (LOCAL | REMOTE);
 
+		release_http_object_request(&obj_req);
+
 		/* Try fetching packed if necessary */
 		if (request->obj->flags & LOCAL) {
-			release_http_object_request(&obj_req);
 			release_request(request);
 		} else
 			start_fetch_packed(request);