Bug 17569: Koha::Patrons - Move GetUpcomingMembershipExpires to search_upcoming_membe...

Bug 17569: Koha::Patrons - Move GetUpcomingMembershipExpires to search_upcoming_membership_expires

This patchset moves the C4::Members::GetUpcomingMembershipExpires
subroutine code to the Koha::Patrons->search_upcoming_membership_expires
method.
This subroutine was used from only 1 place, so it's an easier to move.

Test plan:
Use the membership_expiry.pl cronjob script using the different
options.
The behavior should be the same as prior to this patch.

  prove t/db_dependent/Koha/Patrons.t
should return green

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>