federation/send_queue.py: fix usage of LaterGauge

Fixes a startup crash due to commit df9f72d9e5fe264b86005208e0f096156eb03e4b
"replacing portions".

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py

index 3dcc629d44..9f1142b5a9 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -75,7 +75,7 @@ class FederationRemoteSendQueue(object):
         # changes. ARGH.
         def register(name, queue):
             LaterGauge("synapse_federation_send_queue_%s_size" % (queue_name,),
-                       "", lambda: len(queue))
+                       "", [], lambda: len(queue))
 
         for queue_name in [
             "presence_map", "presence_changed", "keyed_edu", "keyed_edu_changed",