Don't provide a password for sasl authentication.
When a sasl parameter is given (and used) the password parameter is not
used by Net::LDAP. If indeed a password is required it has to be passed
in the Authen::SASL object, not as parameter to bind.
So drop the password parameter which stops trying (and failing) to use
password authentication sometimes if in Net/LDAP.pm the iteration over
%ptype hits its 'password' member before the 'sasl' member.