CoreCon: Remove incorrect argument from SendFile()

This argument is apparently a typo in the MSDN docs. It is not
documented and not present in assembly of actual users of this API.
This change corrects all the users of the API in qttools.

Change-Id: I9cad60b3218a55271d805dad95cda4068aead21a
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>