Remove dead code for setting device specific rules.

It wasn't possible to hit the code from the API because of a typo
in parsing the request path. Since no-one was using the feature
we might as well remove the dead code.

synapse/push/httppusher.py

@@ -23,12 +23,11 @@ logger = logging.getLogger(__name__)
 
 
 class HttpPusher(Pusher):
-    def __init__(self, _hs, profile_tag, user_id, app_id,
+    def __init__(self, _hs, user_id, app_id,
                  app_display_name, device_display_name, pushkey, pushkey_ts,
                  data, last_token, last_success, failing_since):
         super(HttpPusher, self).__init__(
             _hs,
-            profile_tag,
             user_id,
             app_id,
             app_display_name,