message: use None instead of MatchVersione::None.strip_id()
diff: @@ -629,8 +629,8 @@ mod test {
  let release_id = release("0.3.0", db);
  let query = "UPDATE releases SET yanked = true WHERE id = $1 AND version = '0.3.0'";
  db.conn().query(query, &[&release_id]).unwrap();
  - assert_eq!(version(None, db), MatchVersion::None.strip_id());
  - assert_eq!(version(Some("0.3"), db), MatchVersion::None.strip_id());
  + assert_eq!(version(None, db), None);
  + assert_eq!(version(Some("0.3"), db), None);
  release("0.1.0+4.1", db);
  assert_eq!(version(Some("0.1.0+4.1"), db), exact("0.1.0+4.1"));
  