Two minor fixes in the kasp system test:
1. A wrong comment in ns3/setup.sh (we are subtracting 2 hours, not
adding them).
2. 'get_keyids' used bad parameters "$1" "$2" when 'check_numkeys'
failed. Also, 'check_numkeys' can use $DIR, $ZONE, and $NUMKEYS
directly, no need to pass them.
(cherry picked from commit 5be26898c0)