fix crash on non-resolveable URLs

eventlooper.py

@@ -49,6 +49,8 @@ def fetch_page(url):
 	except IOError as e:
 		logger('warn', 'failed: ' + e.errno)
 	
+	return (None, None)
+
 def extract_title(url):
 	if 'repo/urlbot.git' in url:
 		logger('info', 'repo URL found: ' + url)