Bug 19752: offline_circ/service.pl - Return HTTP status 401 when authentication faile...

Bug 19752: offline_circ/service.pl - Return HTTP status 401 when authentication failed and add option nocookie

Test plan:

- Apply this patch,
- log in to Koha,
- go to cgi-bin/koha/offline_circ/service.pl with no valid user
  and password as parameters and nocookie set to 1. i.e:
  cgi-bin/koha/offline_circ/service.pl?userid=alex&password=wrongpass&nocookie=1,
- auth should fail
- check that the response code is 401

Signed-off-by: Maksim Sen <maksim.sen@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>