[blight] 19005: Remove unused driver sources.

Remove unused driver sources.
Deleted: trunk/reactos/lib/mesa32/src/drivers/beos/
Deleted: trunk/reactos/lib/mesa32/src/drivers/directfb/
Deleted: trunk/reactos/lib/mesa32/src/drivers/dos/
Deleted: trunk/reactos/lib/mesa32/src/drivers/dri/
Deleted: trunk/reactos/lib/mesa32/src/drivers/fbdev/
Deleted: trunk/reactos/lib/mesa32/src/drivers/ggi/
Deleted: trunk/reactos/lib/mesa32/src/drivers/glide/
Deleted: trunk/reactos/lib/mesa32/src/drivers/osmesa/
Deleted: trunk/reactos/lib/mesa32/src/drivers/svga/
Deleted: trunk/reactos/lib/mesa32/src/drivers/x11/