install x86 vcredist only if it is necessary

Change-Id: I767d33719ecfb71af64ca28a18b7f0ab2077fd18
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>
Reviewed-by: Akseli Salovaara <akseli.salovaara@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>