initscripts: Make /etc/timestamp consistent again.
Commit cc8695 changed the way timestamps were handled
and added some extra munging to be able to compare them
reliably. This change makes the timestamp value the same
everywhere and simplifies how the check to set the system
clock based on the timestamp is done.
Also, if the value stored in /etc/timestamp is newer
[at all] than the current system time, set the system clock
from the stored value, down to the minute, not just the day.
