Fix #661 show proper tracker host when ending in .co.uk, .com.au, etc..

deluge/core/torrent.py

@@ -520,6 +520,9 @@ class Torrent:
                 host = (url.hostname or 'DHT')
                 parts = host.split(".")
                 if len(parts) > 2:
+                    if parts[-2] in ("co", "com"):
+                        host = ".".join(parts[-3:])
+                    else:
                         host = ".".join(parts[-2:])
                 return host
         return ""