ovpnclients.dat: Fix adjusting input dates

ovpnclients.dat: Fix adjusting input dates

This patch changes that we no longer interpret any dates put in by the
user as UTC. They used to be converted into localtime because, although
they have already been in local time.

This went unnoticed since in Europe we are close (enough) to UTC that
there is no significant discrepancy on the report. However, being in
North America is enough to generate confusing reports.

Reported-by: Paul <kairis@gmail.com>
Fixes: #12768
Tested-by: Jon Murphy <jon.murphy@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>