message: directly print error only if there is more than one job in the queue
diff: @@ -182,15 +182,15 @@ impl<'a> JobQueue<'a> {
  match result {
  Ok(()) => self.finish(key, cx)?,
  Err(e) => {
  - handle_error(&*e, &mut *cx.config.shell());
  -
  if self.active > 0 {
  + error = Some(human("build failed"));
  + handle_error(&*e, &mut *cx.config.shell());
  cx.config.shell().say(
  "Build failed, waiting for other \
  jobs to finish...", YELLOW)?;
  }
  if error.is_none() {
  - error = Some(human("build failed"));
  + error = Some(e);
  }
  }
  }
  