Bug 24353: [19.05] Correct display of privacy_guarantor_checkouts on moremember.pl

Bug 24353: [19.05] Correct display of privacy_guarantor_checkouts on moremember.pl

The variable for 'Show checkouts to guarantor' was incorrect so
it would always show as 'No' on the Details tab in the patron
account in staff.

To test:
- find/create a patron with a guarantor
- Set AllowStaffToSetCheckoutsVisibilityForGuarantor and AllowPatronToSetCheckoutsVisibilityForGuarantor to Allow
- Edit patron to set Show Checkouts to Guarantor to Yes
- Confirm patron incorrectly shows "No" on moremember.pl (Details tab)
- Apply patch
- Confirm the display changes to "Yes"
- Change the value to "No" in the patron record
- Verify that the display changed accordingly

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
RMaint: pushed to 19.05.x
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>