xorg: does not upgrade cleanly

Current xlibs/X.Org packages do not upgrade cleanly from Warty:
  * xserver-xfree86 Debconf questions not unregistered/migrated.
    + e.g. users will get asked whether they want xserver-xorg or
xserver-xfree86 -> this is bogus
  * font migration to TTF not quite complete
    + keep xfonts-* installed
  * XKB does not work
    + fd.o xlibs/xkbfile bad interactions with x.org xc/lib/xkbfile suspected
  * all packages using /usr/lib/X11 and /usr/include/X11 need to ensure that
these are not symlinks before they install