Neither virThreadInitialize or virThreadOnExit do anything since we
dropped the Win32 threads impl, in favour of win-pthreads with:

  commit 0240d94c
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Wed Jan 22 16:17:10 2014 +0000

      Remove windows thread implementation in favour of pthreads
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>