Initialize the DCB structure before using it

Please refer to the MSDN documentation for details:

http://msdn.microsoft.com/en-us/library/windows/desktop/aa363214%28v=vs.85%29.aspx

and

http://msdn.microsoft.com/en-us/library/windows/desktop/aa363201%28v=vs.85%29.aspx

Change-Id: Id60f6d1b4a9237c2ae74063ac52221f42761b004
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>