Bug 11998: Make HoldsQueue.t tests pass [TO REVERT]

Bug 11998: Make HoldsQueue.t tests pass [TO REVERT]

This patch should not be the way to make these tests pass.
The prefs should not be updated using set_preference, it will modify the
values in the cache.

I have no idea how to make them pass using the correct way, please help
:)

Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>
Signed-off-by: Jacek Ablewicz <abl@biblos.pk.edu.pl>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com
(cherry picked from commit 3907401a6d293872ca1fb46c90da029b91d37e31)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>