1. Commit 8b99809a ("compel: make plugins .a archives") changed the
   suffix of compel plugins, so this test no longer compiles.

2. "compel plugins" can print auxiliary plugins now, let's use it.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>