[3/3] winhttp: Convert string data to UTF-8 and add a corresponding content type header.

[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=15333

Your paranoid android.


=== W2K3R2SESP2 (32 bit winhttp) ===
winhttp.c:2158: Test failed: got 80072f78