Don't log unknown cache warnings in workers

synapse/replication/slave/storage/_base.py

@@ -54,7 +54,9 @@ class BaseSlavedStore(SQLBaseStore):
                 try:
                     getattr(self, cache_func).invalidate(tuple(keys))
                 except AttributeError:
-                    logger.info("Got unexpected cache_func: %r", cache_func)
+                    # We probably haven't pulled in the cache in this worker,
+                    # which is fine.
+                    pass
             self._cache_id_gen.advance(int(stream["position"]))
         return defer.succeed(None)