Bug 20003: Fix showing number of remaining checkouts during checking in

Bug 20003: Fix showing number of remaining checkouts during checking in

Test plan:
0) Do not apply the patch
1) Have a patron with more then one checkout
2) Return one of patron's checkout and confirm the remaining number of
checkout is not shown
3) Apply the patch
4) Try it again and confirm the number is now shown

Signed-off-by: Roch D'Amour <roch.damour@inlibro.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>