Windows: afslogon MapAuthError

Windows: afslogon MapAuthError

return WN_NET_ERROR (ERROR_UNEXP_NET_ERR) to indicate a problem
with this network provider when an error occurs instead of
returning WN_NET_SUCCESS.

Reviewed-on: http://gerrit.openafs.org/7629
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 7adb93cf51d56936d51b70758a959342728fea56)

Change-Id: I35f455ff1068418336c4ac11cf57027f3afe4787
Reviewed-on: http://gerrit.openafs.org/8629
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>