Remove deprecated util.py functions compress, get_qcow2_files, and qcow2_to_raw
Remove deprecated util.py functions compress, get_qcow2_files, and qcow2_to_raw

- We have been pulling .raw.xz's for some time now since they are now outputted
  by all Koji createImage build tasks that complete

- Compression is no longer needed since we don't download anything locally
  and downloader.py is gone

fedora-infra/fedimg,fedora-infra/fedimg