Bug 36508: Refresh patron object when updating category

Bug 36508: Refresh patron object when updating category

To test:
1 - Find a ptron, I sued #45 in KTD, note their category
2 - Update them from one category to another using finesunder:
    perl misc/cronjobs/update_patrons_category.pl -f ST -t S --finesunder=5.00 --where "me.borrowernumber=45" -v -c
3 - Check their modification log (I told you to enabled BorrowersLog,
    right?)
4 - See many fields reported changed
5 - Apply patch
6 - Repeat, but change the to and from options
    perl misc/cronjobs/update_patrons_category.pl -f S -t ST --finesunder=5.00 --where "me.borrowernumber=45" -v -c
7 - Note only one column changed in the logs
8 - Ask for unit tests

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit cae2efd69d8ad63822914377733f9819889a0ec1)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>