cifs: fix regression in very old smb1 mounts

BZ: 215375

Fixes: 76a3c92e ("cifs: remove support for NTLM and weaker authentication algorithms")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>