[turba] deleting LDAP entries fails: "VFS not supported for this object."

[Bernhard Erdmann]

Hi,

trying to delete a turba (version 3.0.12) contact results in the  
message "VFS not supported for this object." and the object is not  
deleted. The backend is OpenLDAP.

Changing preferences in conf.php from a) to b) does not make a difference.

a)
$conf['documents']['type'] = 'horde';

b)
$conf['documents']['params']['vfsroot'] = '/var/lib/horde4';
$conf['documents']['type'] = 'File';