Bug#488039: policy: chown uses owner:group not owner.group

[Ian Jackson <ian@davenant.greenend.org.uk>]

Kurt Roeckx writes ("Bug#488039: policy: chown uses owner:group not owner.group"):
> There are several places in policy that use something like "root.root",
> when talking about the owner and group of a file.  People used to use
> that notation to separate the owner and group, and it
> still works, but the proper notation would be "root:root".

What is wrong with <user>.<group> ?  I see that it's not currently
documented but it has worked forever and I hope it's not going away.

Ian.