samba3.blackbox.smbclient_auth.plain will fail against
ad_member & nt4_member (because these envs don't
support SMB1) so we don't run these tests where either
'LANMAN2' or 'NT1' are in the options, in these cases
to get coverage so we use nt4_dc_smb1
Creating new envs for such a small amount of strictly SMB1 tests anyway
seems overkill. For the moment just create specific knownfail entries
and remove the associated entries from skip_smb1_fail
Signed-off-by: Noel Power <npower@samba.org> Reviewed-by: Ralph Boehme <slow@samba.org>