Add Japanese error docs.

See: http://issues.apache.org/bugzilla/show_bug.cgi?id=11521

Submitted by: TAKAHASHI Makoto <hobbit.makoto at nifty.ne.jp>
Reviewed by: Nobuyuki Morita <marika at plum.freemail.ne.jp>, 
             yoshiki, 
             kawai


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@124566 13f79535-47bb-0310-9956-ffa450edef68