-dfilter overwrites any previous filter. The overwritten filter is
leaked. Leaks since the beginning (commit 3514552, v2.6.0). Free it
properly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1466011636-6112-2-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>