Making SetThreadPriorityBoost claim success

[Dan Kegel]

http://bugs.winehq.org/show_bug.cgi?id=22280 just got another dup.

How awful would it be to make SetThreadPriorityBoost just
return success, as in the patch attached to

http://bugs.winehq.org/show_bug.cgi?id=22280#c1

http://bugs.winehq.org/attachment.cgi?id=27224&action=diff&context=patch&collapsed=&headers=1&format=raw

?  We'd have to mark one more test TODO_WINE.

Related if catty discussion:
http://www.codinghorror.com/blog/2006/08/thread-priorities-are-evil.html