Fix pyflake warnings and add a FIXME comment to deal with auth_chains received when joining
Fix pyflake warnings and add a FIXME comment to deal with auth_chains received when joining

illicitonion/synapse,TribeMedia/synapse,matrix-org/synapse,iot-factory/synapse,iot-factory/synapse,illicitonion/synapse,rzr/synapse,howethomas/synapse,rzr/synapse,illicitonion/synapse,iot-factory/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,howethomas/synapse,matrix-org/synapse,rzr/synapse,matrix-org/synapse,iot-factory/synapse,howethomas/synapse,TribeMedia/synapse,matrix-org/synapse,howethomas/synapse,TribeMedia/synapse,TribeMedia/synapse,iot-factory/synapse,howethomas/synapse,rzr/synapse,illicitonion/synapse,rzr/synapse,illicitonion/synapse