call SetLastError in NotifyAddrChange/NotifyRouteChange, to make apps can get
WSA_IO_PENDING error code after async operation through GetLastError.

Thanks to Sebastian Lackner for comments.

superseded patch 107390.
---
 dlls/iphlpapi/iphlpapi_main.c  | 18 ++++++++++++++++--
 dlls/iphlpapi/tests/iphlpapi.c | 39 +++++++++++++++++++++++----------------
 2 files changed, 39 insertions(+), 18 deletions(-)