Bug 28118: Default to current branch when placing hold

Bug 28118: Default to current branch when placing hold

During bug 27071 development, this line got inadvertedly changed. This
patch restores the original behaviour.

To test:
1. Search for a title
2. Go try place a hold
=> FAIL: Look at the HTML, there's no pickup location with
selected="selected"
3. Switch branch and repeat 2
=> FAIL: Still the same
4. Apply this patch
5. Repeat 2 and 3
=> SUCCESS: Branch is selected, chosen current branch is picked
6. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>