ANGLE: fall back to warp mode in case of standard VGA driver

The combination of vendor and device ID being 0000 indicates, that the
standard VGA driver is used, and happens when using Qt in a:
  - Windows 7 machine without proper GPU drivers
  - Windows 7 machine with disabled GPU
  - HyperV vm

The default driver does neither support D3D9 nor D3D11 properly so that
we have to fall back to warp mode for ANGLE.

Change-Id: Ia766e32d680c910a50ec3d6b5002892cdb90fdbb
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>