Fix incomplete sar output when end time crosses 24H boundary

sar output was incomplete when used with a file containing data
from two consecutive days and end time crossed 24 hour boundary.
A typical invocation like:

sar -A -s 21:50:00 -e 01:30:00 -f /path/to/datafile

resulted in CPU statistics being displayed only.

This patch fixes the problem and all selected activities are now
displayed.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>