Bug 15037: Correctly check the patron categories on displaying the Batch checkout tab

Bug 15037: Correctly check the patron categories on displaying the Batch checkout tab

When checking for the patron categories allowed to use the batch
checkout, the comparison should be strict (eq).

Test plan:
0/ Do not apply this patch
1/ Create 2 patron categories ST and S
2/ Enable BatchCheckouts and define BatchCheckoutsValidCategories = S
3/ Create 2 patrons, 1 in the ST category and the other one in S
4/ On the patron detail page, you should see the "batch checkout" tab
for both patron
5/ Apply this patch
6/ The tab should only be displayed for the patron S

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Tested using an 'S' patron and allowing 'ST' patrons only, worked as expected.
Also tried setting &batch=1 to force it to show the batch page, and it says
I'm not allowed to do batch checkouts for that patron. Great!

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