Call RetryLimiter correctly (#5340)

Fixes a regression introduced in #5335.

changelog.d/5340.bugfix

+Fix a bug where we could rapidly mark a server as unreachable even though it was only down for a few minutes.
+

synapse/util/retryutils.py

@@ -97,7 +97,12 @@ def get_retry_limiter(destination, clock, store, ignore_backoff=False, **kwargs)
 
     defer.returnValue(
         RetryDestinationLimiter(
-            destination, clock, store, retry_interval, backoff_on_failure, **kwargs
+            destination,
+            clock,
+            store,
+            retry_interval,
+            backoff_on_failure=backoff_on_failure,
+            **kwargs
         )
     )