def cancel(id)
      Log.warn "Cancelling job id #{id}"
      job = @jobs_by_id[id]
      job.status = Executor::STATUS_ERROR
      job.owner = nil
      job.time_end = Time.now
      @queue.delete(job)
    end
def cancel(id)
      Log.warn "Cancelling job id #{id}"
      job = @jobs_by_id[id]
      job.status = Executor::STATUS_ERROR
      job.owner = nil
      job.time_end = Time.now
      @queue.delete(job)
    end
Cancel a job by id