Bug 15188: Do not remove unused auths if zebra is not reachable

Bug 15188: Do not remove unused auths if zebra is not reachable

Other conn errors should be checked (wrong user/pwd, etc.)

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit a60943bc1b28696459ea5a28df9874083b9f0966)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
(cherry picked from commit 67b3f0196ea4129488193f27fd3e28591ff5f33d)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>