Have ranking listen on localhost by default (#1304)

Author: veluca93

config/cms.ranking.conf.sample

@@ -3,7 +3,7 @@
     "_help": "fields starting with '_' are meant to be comments.",
 
     "_help": "Listening address for RankingWebServer.",
-    "bind_address": "",
+    "bind_address": "127.0.0.1",
 
     "_help": "Listening port for RankingWebServer.",
     "http_port": 8890,