Add a Throttle check shortly after boot.

Throttle is useless when ntp and imsi are not yet ready.  In the real world
the second check won't happen for 10 minutes letting people do what they want
for 10 minutes each boot.  Trim this down with a quicker first check.

bug:2614247
Change-Id: I84ec33f31e8fed37b3933482fbc187b8e9e94e79