LDAP: Remove unused option ldap_user_uuid
    
    There is problem with OpenLDAP server and dereferencing of attributes
    that is not in the schema  of the server?
    
    sh-4.2$ ldapsearch -x -LLL -h openldap.server.test -b 'dc=example,dc=com' \
                       -E 'deref=member:uid,dummy_attr' cn=ref_grp
    Protocol error (2)
    Additional information: Dereference control: attribute decoding error
    sh-4.2$ echo $?
    2
    
    The attribute nsUniqueID is a 389-only, non-standard attribute.
    It is an operational attribute that is not in the rfc2307bis nor inetOrgPerson
    nor posixAccount schema. It was a default value of option ldap_user_uuid,
    but it was not use anywhere.
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/2383
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>