[PATCH] Enable X11DRV_DIB_GetImageBits_8 in all cases and optimize X11DRV_DIB_GetNearestIndex to fix bug 2666 and other strange behavior

[Frédéric Delanoy]

Please do not include bug number in commit message summary line.
Put something like 'fixes bug 123 in the commit header

See http://wiki.winehq.org/SubmittingPatches for more info (e.g.
"subject line" and "include a description" sections)

Frédéric