Give Overdues a few whacks with perltidy

Give Overdues a few whacks with perltidy

This was, an in part still is, some of the worst-formatted code in Koha.

Also made a few minor changes:
~ removing sth->finish
~ adding comment
~ removed whitespace error trailing spaces
~ use trinary op, like: return ( $debarredstatus eq '1' ? 1 : 0 );

Note that the logic is the same, even where I condsider it faulty.
(In the exampe case, because $debarredstatus may be undef.)

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>
Signed-off-by: Henri-Damien LAURENT <henridamien.laurent@biblibre.com>