Univention Corporate Server 3.2 erratum 130 (bugfix)

When an object is renamed in LDAP, the old relative distinguished name (RDN)
values are kept by default. This leads to situations, where an attribute
declared as single-valued may become multi-valued, which breaks the
replication to Samba 4 and confuses several other listener modules.
This erratum changes the low-level Univention LDAP code to remove the old RDN
values as well, as all other code paths already do so.