Don't try to cleanup libselinux and libaudit.

Because we are not shutting down the other threads first another
thread might work on a query before the process shuts down.  In this
case the now uninitialized libselinux and libaudit might be used.
Just don't free the resources.  It's not necessary anyway because
the process is about to terminate.
(cherry picked from commit 9e471dad)
(fixed ChangeLog entry by pasky)