Add a timeout clause to the rsync method

Under normal operation, the rsync call can hang on the cluster. Usually, this is because the cluster (or target cluster) is not configured to enable ssh_to_job. In this MR, a timeout of 30s is added so that the approach will fail and revert to the spool. In testing, I found that if it wasn't successful after a few seconds, it would hang for more than 10 minutes, so a 30s timeout seems like a medium ground.