This is done by adding a
```xml
<d:eq>
<d:prop>
<oc:owner-id/>
</d:prop>
<d:literal>$userId</d:literal>
</d:eq>
```
clause to the search query.
Searching by `owner-id` can only be done with the current user id
and the comparison can not be inside a `<d:not>` or `<d:or>` statement
Signed-off-by: Robin Appelman <robin@icewind.nl>