Unbreak SASL
    
    Patch bc76428246c4ce532abd0eadcd539069fc1d94a8 changed the data
    type of sasl_minssf from int to ber_len_t. Unfortunately, default
    value of ldap_sasl_minssf is -1 but ber_len_t is defined as
    unsigned long. This made SASL mechanism inoperative.