Bug 987059: Stopage of the redirection /ja/about/ to /b/ja/about/

Mozilla Japan are merging their contents into mozilla.org.
Almost all contents can be merged, but there are some contents which can not be, 
because they have Japanese specific contents.

/about is the typical page which we can not merge into mozilla.org.
It contains Mozilla Japan's information and history.

We want to navigate Japanese users to http://mozilla.jp/about, who access to http://mozilla.org/ja/about.
The reason why we want to set such a redirection is available in https://bugzilla.mozilla.org/show_bug.cgi?id=987059. 

If this pull-request is merged, we can set the redirection for /about in mozilla.com/ja/.htaccess.
The destination will be specified in that file.