WinGui: Fix a culture issue with the samplerate query generation.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5828 b64f7644-9d1e-0410-96f1-a4d463321fa5
WinGui: Use a specific culture to make sure . is used rather than ,

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5829 b64f7644-9d1e-0410-96f1-a4d463321fa5