packaging/: Delete

packaging/: Delete

This is obsolete for a few reasons. The spec file is out of date (mostly the
%files, but also the BRs), and further down the line we'll need to use `make
dist` so we pick up vendored Rust sources. So the "git archive" approach won't
work for much longer anyways.

This came up in https://mail.gnome.org/archives/ostree-list/2017-February/msg00005.html

Basically, anyone who wants to build packages should look at the upstream
dist-git - until such time as e.g. Fedora learns to support pulling spec files
from upstream.

Closes: #670
Approved by: giuseppe