Tell search engine bots not to crawl our git mirrors.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/web/trunk@4307 92316355-f0b4-4df1-b90c-862c8a59935f

www/robots.txt

@@ -9,6 +9,10 @@ Disallow: .svn
 Disallow: /cgi-bin/trac.cgi
 Disallow: /log
 
+# Don’t crawl git repos
+Disallow: /git/*.git/*
+Disallow: /git/*.git.broken/*
+
 # "This robot collects content from the Internet for the sole purpose of
 # helping educational institutions prevent plagiarism. [...] we compare
 # student papers against the content we find on the Internet to see if we