Bug 10606: Remove MySQLism in GetUpcomingDueIssues

Bug 10606: Remove MySQLism in GetUpcomingDueIssues

To test:

[1] Arrange to have at least one loan in your test database due
    one day from now.
[2] Run misc/cronjobs/advance_notices.pl -c -n -v -m=2
    and note the number of loans reported.
[3] Apply the patch.
[4] Run misc/cronjobs/advance_notices.pl -c -n -v -m=2 again
    and verify that the number of loans reported remains the same.

Sponsored-by: Universidad Nacional de Cordoba
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
All tests and QA script pass.
Also tested with unit tests from bug 10719.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>