Quietly keep locale en_US.UTF-8 on Windows

We're not sure if anything cares what we set the locale to this way on Windows.
For now we'll leave it as en_US.UTF-8 until we find a use case that indicates
we should do something else.
Merge pull request #2122 from opscode/btm/windows-locale

Quietly keep locale en_US.UTF-8 on Windows