LP#1386260: DST bugs in perl live tests (03-overdue_circ.t)

Use safer date math to handle bug with DST

Signed-off-by: Jason Etheridge <jason@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>
LP#1386260: DST bugs in perl live tests (04-overdue_with_closed_dates.t)

more fixes

Signed-off-by: Jason Etheridge <jason@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>