Bug 13697: Syspref to not add a fee when a patron changes to a category with enrolmen...

Bug 13697: Syspref to not add a fee when a patron changes to a category with enrolment fee

By default this syspref is "Do" to keep the previous behaviour.

Test plan :

1/ create 2 categories (A & B). B with enrolment fee
2/ create a patron in category A
3/ change the patron category from A to B
4/ check that the patron has an enrolment fee to pay

Apply the patch

1/ create a new patron in category A
2/ change the patron category from A to B.
3/ check that the patron has an enrolment fee to pay
4/ change the system preference 'FeeOnChangePatronCategory' to 'Don't';
5/ create a new patron in category A
6/ change the patron category from A to B
7/ check that the patron has no enrolment fee to pay

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