Bug 29356: Pickup location dropdowns should perform 'contains' searches

Bug 29356: Pickup location dropdowns should perform 'contains' searches

When placing a hold, the dropdowns for selecting a pickup library automatically right-truncate, so one can type "cen" and find Centerville.

On the Libraries page in Admin, however, the search box both left- and
right-truncates, so one can type "en" and find Centerville.

This patch makes the search perform 'contains' searches.

To test:
1. Try placing a hold. Make sure your rules allow Centerville to be a
   valid pickup location.
2. Search 'cen'
=> SUCCESS: Centerville shows
3. Search 'en
=> FAIL: Centerville doesn't show
4. Apply this patch and reload
5. Repeat 2
=> SUCCESS: Works!
6. Repeat 3
=> SUCCSS: Centerville shows!
7. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>