Obviously, we should g_free the task after trace point and offset
update.

Reported-by: Coverity (CID 1428756)
Fixes: 4ce5dd3e
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200507183800.22626-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>