xdvi script broken in potato

[Denis Barbier <barbier@imacs.polytechnique.fr>]

I already reported a bug against xdvi, because it creates a temporary file
but does not always destroy it.

Another bug is much more grave because it breaks xdvi call with options.
One has to replace
  filename=${1+"$@"}
so that filename is set to the last argument, and not first.
A simpler approach is to remove our diffs from this script.

Denis