Notification alert every 5s and start after 30s.

Justification: Most users will not need prompting, so for them a
notification will be an annoyance.  So we only notify if the no
password has been entered for 30 seconds.

Once a notification sound is made, we need to make it frequently so
the user can locate the device.

Change-Id: Ibf531aec89b5e3b3c72eaa36016bcc4cac1d6493