message: rpm_ostree/deploy: do not error on exit code 77
  This relaxes the deploy logic in order to better behave in cases
  where the target revision is already staged locally.
  This acknowledges the fact that `rpm-ostree deploy` is using
  `77` as a positive exit-code to signal that no changes had to be
  performed.
diff: @@ -38,8 +38,12 @@ fn invoke_cli(release: Release) -> Fallible<Release> {
  .arg(format!("revision={}", release.checksum))
  .output()
  .with_context(|e| format_err!("failed to run rpm-ostree: {}", e))?;
  + let exit_code = cmd.status.code().unwrap_or(-1);
  - if !cmd.status.success() {
  + // This CLI verb has multiple positive exit codes:
  + // * 0 => "ok, changes applied"
  + // * 77 => "ok, unchanged"
  + if !(exit_code == 0 || exit_code == 77) {
  bail!(
  "rpm-ostree deploy failed:\n{}",
  String::from_utf8_lossy(&cmd.stderr)
  