timestamp-service: don't restore time on shutdown

load-timestamp.sh --save should only save the current systemtime and not
evaluate /etc/timestamp and change the systemtime.
If the systemtime has been changed to something in the past of /etc/timestamp
then that change should be accepted without further checks.

While at it correct the comment. The RTC/hwclock is not touched by the
timestamp service. This is a copy paste error from the init.d implementation
in openembedded-core/meta/recipes-core/initscripts/initscripts-1.0/bootmisc.sh

Signed-off-by: Max Krummenacher <max.oss.09@gmail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>

recipes-core/systemd/timestamp-service/load-timestamp.sh

@@ -1,8 +1,11 @@
 #!/bin/sh
 
-# Set the system clock from hardware clock
-# If the timestamp is 1 day or more recent than the current time,
-# use the timestamp instead.
+if [ "$1" != "--save" ] ; then
+
+# Set the system clock from timestamp file
+# if the timestamp is 1 minute or more recent
+# than the current systemtime.
+
 SYSTEMDATE=$(/bin/date -u "+%4Y%2m%2d%2H%2M")
 
 TIMESTAMP=$(/bin/cat /etc/timestamp 2>/dev/null)
@@ -12,7 +15,7 @@ if [ $SYSTEMDATE -lt $TIMESTAMP ] 2>/dev/null ; then
 	/bin/date -u ${TIMESTAMP#????}${TIMESTAMP%????????}
 fi
 
-if [ "$1" = "--save" ] ; then
+else
+# Store the current systemtime in /etc/timestamp
 	/bin/date -u +%4Y%2m%2d%2H%2M > /etc/timestamp
 fi
-