cannot build packages following instructions

I'm trying to build/rebuild the Debian packages and have tried following the instructions.

```
% ./build_packages citus nightly
/Users/jesse/git/citus/packaging/fetch_build_files: could not fetch build tarball from https://github.com/citusdata/packaging/archive/debian-citus.tar.gz
/Users/jesse/git/citus/packaging/fetch_build_files: HTTP code was: 404
```

It looks like the `debian-citus` branch name has been removed, and is now called `all-citus` instead.

If I correct this, I eventually run into other problems though:
```
% ./build_packages citus release
...
/scripts/fetch_and_build_deb: line 78: releasepg: unbound variable
```

Are there up to date instructions somewhere on how to build the packages?