Log more timing information from init.

Also make important events in init's life NOTICE rather than INFO,
and ensure that NOTICE events actually make it to the kernel log.

Also fix the logging so that if you have a printf format string
error, the compiler now catches it.

Also give messages from init, ueventd, and watchdogd distinct tags.
(Previously they'd all call themselves "init", and dmesg doesn't
include pids, so you couldn't untangle them.)

Also include the tag in SELinux messages.

Bug: 19544788
Change-Id: Ica6daea065bfdb80155c52c0b06f346a7df208fe