patch review requested for 9007: "script/plugin install -x" on Windows when using _svn directories

Greetings,

My patch for using "script/plugin install -x" on Windows when
Subversion working copies use _svn instead of .svn directories is
ready for review. The ticket is here

http://dev.rubyonrails.org/ticket/9007

I had a hard time attaching the patch to the ticket. Ultimately, I had
to upload it elsewhere and link to it from the ticket, which I noted
in a comment. Here's the URL

http://demmer12.fastmail.us/plugin_install_underscore_svn.diff

Thanks,
Craig