Put back modprobe blocks for nouveau and radeon, for now.
Perhaps "blacklist" should be enough,
or removing these at boot (so that nouveau and radeon also work).
Also, update ld.so.cache-* files when needed).
Blacklist nouveau and blacklist radeon, so we can later load nvidia
and fglrx.  But do not set the "off"-alias, because in nouveau case
that apparently may cause the loading of nvidia?  (I *am* starting to
get totally confused by this stuff).