Round peer rating to 2 decimal places before saving knownnodes

src/knownnodes.py

@@ -37,6 +37,7 @@ def json_serialize_knownnodes(output):
     _serialized = []
     for stream, peers in knownNodes.iteritems():
         for peer, info in peers.iteritems():
+            info.update(rating=round(info.get('rating', 0), 2))
             _serialized.append({
                 'stream': stream, 'peer': peer._asdict(), 'info': info
             })