Problems with 'raw' rssMode when producing XML view of issue filter (in single-xml.vm)

The velocity template used when producing the XML view of an issue filter, WEB-INF/classes/templates/plugins/issueviews/single-xml.vm, has an $rssMode variable, which when set to 'raw' should produce the description (and some other fields) unescaped in a CDATA string.

It has two problems.

1. There is no way to pass through the rssMode = 'raw' via the URL (there used to be), and hence this mode is not very useful.

2. If you hack the file to set $rssMode to 'raw', the template breaks whenever the escCdata macro is used with a parameter that is null. For example, this can easily be the case with the environment field. And it breaks in a not so obvious manner.

Attached is a modified single-xml.vm that fixes the second problem. It might not be the most elegant solution though.