libvirtd: Fix order of cleanup processing

libvirtd: Fix order of cleanup processing

Current cleanup processing is ad-hoc at best - it's led to a couple of
strange and hard to diagnose timing problems and crashes.

So rather than perform cleanup in a somewhat random order, let's
perform cleanup in the exact opposite order of startup.

NB: It is possible that virNetlinkEventServerStart fails and we jump
to cleanup before driversInitialized has been set. That could leave
things inconsistent; however, resolution of that possibility is perhaps
more trouble than it's worth to handle.

Signed-off-by: John Ferlan <jferlan@redhat.com>