Bug 7349: corrects sort order for Patron search

Bug 7349: corrects sort order for Patron search

Sorting by cardnumber now works (removed a client-side
sort, the server-side sort is enough).

Signed-off-by: Koustubha Kale <kmkale@anantcorp.com>
1) Verified that before applying this patch, when searching patrons with cardnumber as order by preference, patrons are sorted ny name.
2) Verified that after applying this patch, when searching with cardnumber as order by preference, patrons are correctly sorted by cardnumber.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>