Fix the createOrUpdate function

As said in #704, this function doens't work and I even think it never has worked... (or for a short time)
This function is accessed by the ContactsManager in core. 

cc @DeepDiver1975 


Instead of this switch, a call to [$contact->setPropertyByName($name, $value)](https://github.com/owncloud/contacts/blob/master/lib/contact.php#L562) will probably work and avoid code duplication