nvidia-detect: still return hardware detecttion value when Xorg
detection fails

In cases where Xorg Server detection fails we should still return the
detected hardware value as people rely on this in scripts.

See bug: http://elrepo.org/bugs/view.php?id=426

Signed-off-by: Philip J Perry <phil@elrepo.org>
nvidia-detect: clean up code

Minor code cleanup.

Signed-off-by: Philip J Perry <phil@elrepo.org>
nvidia-detect: bump for 331.20-2 release

Signed-off-by: Philip J Perry <phil@elrepo.org>