Remove unused "OwnershipModel" definition

Author: Thiago Perrotta

index.bs

@@ -1167,10 +1167,6 @@ Issue: Define how this works.
 Each EMCAScript [=Realm=] has a corresponding <dfn>handle object map</dfn>. This is a
 strong [=/map=] from handle ids to their corresponding objects.
 
-<pre class="cddl remote-cddl">
-OwnershipModel = "root" / "none";
-</pre>
-
 <dfn>RemoteReference</dfn> is either a <code>RemoteObjectReference</code>
 representing a remote reference to an existing ECMAScript object in
 [=handle object map=] in the given [=Realm=], or is a <code>SharedReference</code>