wrong ldif file for altering indexes

In the Samba LDAP guide (https://help.ubuntu.com/lts/serverguide/samba-ldap.html) there is a wrong line on the indexes configuration file.

dn: olcDatabase={1}hdb,cn=config
changetype: modify
add: olcDbIndex
olcDbIndex: uidNumber eq
olcDbIndex: gidNumber eq
olcDbIndex: loginShell eq
olcDbIndex: uid eq,pres,sub
olcDbIndex: memberUid eq,pres,sub
olcDbIndex: uniqueMember eq,pres
olcDbIndex: sambaSID eq
olcDbIndex: sambaPrimaryGroupSID eq
olcDbIndex: sambaGroupType eq
olcDbIndex: sambaSIDList eq
olcDbIndex: sambaDomainName eq
olcDbIndex: default sub

On the third line, instead of "add: olcDbIndex" it should be "replace: olcDbIndex"

Another small improvement that can be done is stating that the first line refers to systems using the hdb database. I was using the mdb, and had to change it.