msi: Convert 45 initializations of static const WCHAR towards towards using wide strings.

[Gerald Pfeifer]

On Sun, 25 Oct 2015, Nikolay Sivov wrote:
>> The u"string" format is easier to write, read, and maintain than
>> the {'s','t','r','i','n','g'} format.
> Wasn't this added with C++11?

You are right (unfortunately).  I tested with an older version
of GCC (4.2) and a moderately new version of Clang, and both
stumbled over it.

Patch retracted.  (Would have been too nice.)

Gerald