ws2_32: Fix WSADuplicateSocket implementation

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://newtestbot.winehq.org/JobDetails.pl?Key=2119

Your paranoid android.


=== w7pro64 (32 bit sock) ===
sock.c:528: Test failed: oob_server (a8c): not at the OOB mark: 1