Subversion 1.6 で zsh の補完が失敗する

$ cd /usr/share/zsh/site-functions
$ sudo wget -c http://gvn.googlecode.com/svn/trunk/contrib/zsh/_subversion

- ref.: Re: Subversion 1.5 and ZSH Completion
  http://subversion.tigris.org/ds/viewMessage.do?dsForumId=1065&dsMessageId= ...