dlp: sleep before getting jobs (#463)
dlp: sleep before getting jobs (#463)

Sometimes, GetDlpJob reads a stale version of the job DB. Sleeping for
half a second after receiving the job finished message should prevent
not getting any results. In particular, this should reduce test
flakiness. Also see #462.
GoogleCloudPlatform/golang-samples,GoogleCloudPlatform/golang-samples,GoogleCloudPlatform/golang-samples