[PATCH] po/ja/base.po: Update and fix Japanese translation

[PATCH] po/ja/base.po: Update and fix Japanese translation
o Re-add some translation whice rejected last time by conflicts.
o Delete some lines because which were my own local modefications.
o Revert commented lines at the end of base.po file which deleted by accidental commit.

Signed-off-by: Kentaro Matsuyama <kentaro.matsuyama@gmail.com>