Bug#1405: vim doesn't use update-alternatives

[Ian Jackson <iwj10@cus.cam.ac.uk>]

Package: vim
Version: 3.0-3

 Setting up vim ...
 A link to /usr/bin/vi already exists, so a link will not be made
 A link to /usr/man/man1/vi.1 already exists, so a link will not be made
 Not linking vim to vi in /usr/bin or /usr/man/man1

vim should use update-alternatives instead.  Taking a leaf out of
nvi's postinst:

update-alternatives --install /usr/bin/vi vi /usr/bin/vim 20 \
  --slave /usr/man/man1/vi.1 vi.1 /usr/man/man1/vim.1

would seem appropriate, with a corresponding

if [ $1 != "upgrade" ]
then
  update-alternatives --remove vi /usr/bin/vim
fi

in the prerm.

Ian.