* Copy the contents of the master port japanese/navi2ch-emacs20 to the slave
port
japanese/navi2ch-emacs21 because the former is deprecated and going to be
removed
soon. Adjust it to point to emacs21 by default.
* Adjust the slave port japanese/navi2ch-xemacs21-mule to point to the newly
created master port japanese/navi2ch-emacs21.