jira conversion - five points

Several issues in the jira conversion:

1. The 'whiteboard' field isn't converted:
http://subversion.tigris.org/issues/buglist.cgi?status_whiteboard=.&status_whiteboard_type=regexp
Bert suggests it doesn't need to be.
Markus points out we could add it to the "issue description" instead of tossing it.
(I have no strong opinion)

2. The 'url' field isn't converted. I think it is important: unlike
'whiteboard' it can't be derived from the other fields. For example,
http://subversion.tigris.org/issues/show_bug.cgi?id=4129#desc17 and
issue #4595 both have links on that field that aren't in any other
field, and shouldn't be lost. I propose we add the URL (either as
a custom field, or inline in the Description, whichever is easier)

3. "#desc42" intra-issue and external links will be broken. I suppose
there is nothing we can do to prevent that, and if we wanted to
implement a fix, we could do so easily after the migration, too.

4. Given that an XML export of all issues is only 23MB compressed,
I think we should archive the final XML export on ASF hardware.
(Maybe we can just import it to ^/subversion/archive in the repository?)

5. What mailing list will issue notifications go to?
We already have issues@subversion: https://mail-archives.apache.org/mod_mbox/subversion-issues/

---
So, in summary, I think we should:
- migrate the 'url' field into the description field
- archive the tigris xml export on apache.org