RESPONDERS: Negative caching of local users
This patch adds new option 'neg_cache_locals_timeout' into section
of NSS responder. It allows negative caching of local groups and
users. Default value is 0 which means no caching.
Resolves:
https://fedorahosted.org/sssd/ticket/2928
Reviewed-by: Pavel Březina <pbrezina@redhat.com>