w32: Fix confusion about INVALID_HANDLE_VALUE. Fix leak.
* w32/npth.c (new_thread): Use NULL instead of INVALID_HANDLE_VALUE. (free_thread): Close ->EVENT. (npth_cond_wait): Use NULL instead of INVALID_HANDLE_VALUE. (npth_cond_timedwait): Likewise. (npth_eselect): Use NULL for sock_event.
We cannot change the npth_eselect behavior for EVENTS argument with
INVALID_HANDLE_VALUE.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>