[PATCH] user32: Allow using null driver as a normal graphics driver.

[Jacek Caban]

When explicitly requested by config, Wine will use null driver in the 
same way as we allow using it for invisible winstations.

Signed-off-by: Jacek Caban <jacek(a)codeweavers.com>
---
  dlls/user32/driver.c        | 33 +++++++++++++++++----------------
  programs/explorer/desktop.c | 10 +++++++++-
  2 files changed, 26 insertions(+), 17 deletions(-)