Can set a node as a client

Doesn't currently do anything, but the option is now there.

lib/chutney/TorNet.py

@@ -1030,6 +1030,7 @@ DEFAULTS = {
     'authority': False,
     'bridgeauthority': False,
     'hasbridgeauth': False,
+    'client': False,
     'relay': False,
     'bridge': False,
     'pt_bridge': False,