Update transmission-trackers.py

- update the keyword parameter. The 'host' did not work for me. I changed to name to 'address' according to (`transmissionrpc`'s document)[https://pythonhosted.org/transmissionrpc/reference/transmissionrpc.html#client-object]

Author: scottpedia

transmission-trackers.py

@@ -4,7 +4,7 @@
 # Host, port, username and password to connect to Transmission
 # Set user and pw to None if auth is not required
 client = {
-  'host': 'localhost',
+  'address': 'localhost',
   'port': 9091,
   'user': 'admin',
   'password': 'passwd'