Bug 17872: Fix small error in GetBudgetHierarchy and one of its calls

Bug 17872: Fix small error in GetBudgetHierarchy and one of its calls

In aqbudgetperiods.pl a commented line is removed that contains a
wrong userenv hash key. Should be branch instead of branchcode.

In aqbudgets GetBudgetHierarchy is called with the same wrong userenv
hash key. Should be userenv->{branch}.
This made another bug visible: if you call GetBudgetHierarchy with a
branch and without owner, the where clause should take into account
that the branchcode can be empty (not null).

Test plan:
[1] Run Budgets.t
[2] Run aqbudgets.pl from Administration
[3] Add the show_mine=1 parameter in the URL
[4] Change owner of one of the funds and repeat step 2 and 3.

t/Budgets.t returns green. Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>