make all tests work on Ruby 1.9.1.

Timeout::Error is subclass of RuntimeError not SignalException
on Ruby 1.9.1.

lib/openid/fetchers.rb

@@ -205,15 +205,15 @@ def fetch(url, body=nil, headers=nil, redirect_limit=REDIRECT_LIMIT)
             conn.request_post(url.request_uri, body, headers)
           end
         }
+      rescue Timeout::Error => why
+        raise FetchingError, "Error fetching #{url}: #{why}"
       rescue RuntimeError => why
         raise why
       rescue OpenSSL::SSL::SSLError => why
         raise SSLFetchingError, "Error connecting to SSL URL #{url}: #{why}"
       rescue FetchingError => why
         raise why
       rescue Exception => why
-        # Things we've caught here include a Timeout::Error, which descends
-        # from SignalException.
         raise FetchingError, "Error fetching #{url}: #{why}"
       end