CONFDB: Files domain if activated without .conf
Implicit files domain gets activated when no sssd.conf present
and sssd is started. This does not respect --disable-files-domain
configure option
Resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=1713352
Reviewed-by: Alexey Tikhonov <atikhono@redhat.com>