[FIX]Allow showing the button to do a 'svn up' on an instance to registered users (like the one that added the bug report and instance), and not just ot admins with the right to destroy the instance.

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49029 b456876b-0849-0410-b77d-98878d47e9d5