Added Quota to list of read-only properties.  Last node in NodeUtil is always non-light version.
Added Quota to list of read-only properties.  Last node in NodeUtil is always non-light version.

git-svn-id: 311fcc5b8b03427d323cee07bbb9e5a14d8d22e9@1011 728ff76a-78ac-11de-a72b-d90af8dea425

opencadc/vos,opencadc/vos,opencadc/vos