Bug 32261: Patron autocomplete - do not empty text field

Bug 32261: Patron autocomplete - do not empty text field

The jQuery UI autocomplete is supposed to replace the text field with
the 'value' attribute of the selected item. As it does not exist it's
emptied. We should not replace what the user typed in.

Test plan:
Go to the Koha home page
Select "Search patrons" in the header
Type 'edn', it will return 1 result
Use the down key to select the item (it is not obvious but there is a
little change in the color when you select the item)
=> Without this patch the search field is emptied
=> With this patch applied the search field is not modified

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>