Bug 15524: (QA follow-up) Fix meaningless test

Bug 15524: (QA follow-up) Fix meaningless test

The last test claims to allow a hold when branch=5 and patron=5, but look
at the preceding statements:
    $rule_branch->max_holds(5);
    $rule_branch->update();
    $rule_branch->max_holds(5);
    $rule_branch->insert();
The last insert will not be done, since the record is already present.
A create should have triggered an error on the primary key.
Obviously, we should use $rule_all.

Test plan:
Run the test again.

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