Bug 13240: Remove some code obfuscation

Bug 13240: Remove some code obfuscation

my $bar;
my $foo = $bar->{borrowernumber} ||= {};
$foo->{one} ||= 'something';
$foo->{two}++;

What does $bar contain?

$VAR1 = {
          'borrowernumber' => {
                                'two' => 1,
                                'bar' => 'something'
                              }
        };

Not really obvious.

Maybe something I did not see is hidden.

Test plan:
Verify the digest for DUE and PREDUE work as before.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>