winbindd: don't set mapped_state in winbindd_dual_auth_passdb()

winbindd: don't set mapped_state in winbindd_dual_auth_passdb()

mapped_state is a special hack for authenticate_ldap_simple_bind_send()
in order to avoid some additional work in authsam_check_password_internals()

This doesn't apply here. We should also handle wbinfo -a
authentication UPN names, e.g. administrator@DOMAIN,
even if the account belongs to the local sam.

With this change the behavior is consistent also locally on DCs and
also an RODC can handle these requests locally for cached accounts.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13879
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15003

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>