9p: v9fs_vfs_rename incorrect clunk order

In v9fs_vfs_rename function labels don't match the fids that are clunked.
The correct clunk order is clunking newdirfid first and then olddirfid next.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>