[chirp_users] Can't install chirp on Ubuntu 16.10

The Chirp repo doesn't seem to work with Ubuntu 16.10.

I get errors: W: The repository 'http://ppa.launchpad.net/dansmith/chirp-snapshots/ubuntu yakkety Release' does not have a Release file.

E: Failed to fetch http://ppa.launchpad.net/dansmith/chirp-snapshots/ubuntu/dists/yakkety/main/... 404 Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.