Update Japanese translation
Please merge this changes for Japanese translation.
I'm a Japanese translator in Mailman 2.1. https://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/messages/ja/LC_MESSAGES/mailman.po#L3
Please merge this changes for Japanese translation.
I'm a Japanese translator in Mailman 2.1. https://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/messages/ja/LC_MESSAGES/mailman.po#L3