Bug 643979 - Strange byte sequence for attribute with no values (nsslapd-referral)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=643979
    
    There are two problems being fixed:
    
    1. The cn=config is not supposed to store empty attribute. The
       attrlist_merge_valuearray() has been modified not to create
       a new attribute if the value provided is NULL.
    
    2. If an attribute doesn't have any value, it should not be sent
       to the client. The encode_attr_2() has been modified to check
       whether the attribute has any values before starting to do
       BER-encoding.