transport: fix leaks in refs_from_alternate_cb

The function starts by creating a copy of the static buffer
returned by real_path, but forgets to free it in the error
code paths. We can solve this by jumping to the cleanup code
that is already there.

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

transport.c

@@ -1369,11 +1369,11 @@ static int refs_from_alternate_cb(struct alternate_object_database *e,
 	while (other[len-1] == '/')
 		other[--len] = '\0';
 	if (len < 8 || memcmp(other + len - 8, "/objects", 8))
-		return 0;
+		goto out;
 	/* Is this a git repository with refs? */
 	memcpy(other + len - 8, "/refs", 6);
 	if (!is_directory(other))
-		return 0;
+		goto out;
 	other[len - 8] = '\0';
 	remote = remote_get(other);
 	transport = transport_get(remote, other);
@@ -1382,6 +1382,7 @@ static int refs_from_alternate_cb(struct alternate_object_database *e,
 	     extra = extra->next)
 		cb->fn(extra, cb->data);
 	transport_disconnect(transport);
+out:
 	free(other);
 	return 0;
 }