debian/changelog: Update to new snapshot release

Going to use a git snapshot for the next upload, adjust the changelog
accordingly.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Revert "debian: Use a custom systemd service file"

This reverts commit 2d326600a24021ea63fc030123a0ef12097f63b1. We do not
need the custom file anymore, when using the updated upstream service
file.