Bug#869409: libnotify-bin: add informations about upstream

[c.buhtz at posteo.jp]

Hello Andreas

> The information you're interested in seems to fit into
> the "debian/upstream/metadata" descriptions which you can find out
> more about at https://wiki.debian.org/debian/upstream
> Patches welcome!

This is up to upstream to provide that informations.
https://bugzilla.gnome.org/show_bug.cgi?id=785316

I can not understand why this package was accepted for Debian without
providing this minimal informations.