chutney triggers tor warnings about ExitRelay not being set

All authorities including the bridge authority, all relays:

../chutney/net/nodes/000a/info.log:Sep 15 23:24:25.144 [warn] Tor is running as an exit relay with the default exit policy. If you did not want this behavior, please set the ExitRelay option to 0. If you do want to run an exit Relay, please set the ExitRelay option to 1 to disable this warning, and for forward compatibility.
../chutney/net/nodes/000a/info.log:Sep 15 23:24:25.144 [warn] In a future version of Tor, ExitRelay 0 may become the default when no ExitPolicy is given.

This affects legacy/trac#17011 (moved) when we are trying to force IPv6-only exit connections.

This may also indicate a misconfiguration, or simply me (teor) forgetting ExitRelay 0/1 in the torrc templates.