web: ask crawler bots to hit us less aggressively.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/web/trunk@4868 92316355-f0b4-4df1-b90c-862c8a59935f

www/robots.txt

@@ -5,6 +5,10 @@ User-agent: *
 Disallow: CVS
 Disallow: .svn
 
+# Be gentle
+User-agent: *
+Crawl-delay: 5
+
 # Prevent excessive search engine hits
 Disallow: /cgi-bin/trac.cgi
 Disallow: /log