Bug 21837: Don't set holdingbranch filter using selected homebranch filter

Bug 21837: Don't set holdingbranch filter using selected homebranch filter

To recreate:
1 - Open the overdues report (don't worry if you don't have results)
2 - Choose to filter by homebranch
3 - Note the holdingbranch filter is set to the selected homebranch
4 - Apply patch
5 - Clear filters
6 - repeat
7 - only homebranch is set

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>