server: correctly map mutex acces rights

[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
http://testbot.winehq.org/JobDetails.pl?Key=13534

Your paranoid android.


=== W7PROX64 (64 bit sync) ===
sync.c:160: Test failed: WaitForSingleObject succeeded
sync.c:177: Test failed: ReleaseMutex should have failed with ERROR_NOT_OWNER instead of 5