praekelt/vumi — pull request #664 by jerith (2013-12-04 15:08:06+00:00)
Title: Handle USSDResponse messages in MTN Nigeria USSD tx

Our logs are full of `Packet of type 'USSDResponse' with session id '1859877021' received:` messages. In all the cases I've looked at, these are due to us replying to an inbound message either shortly before or sometime after we receive an 'EndofSession' message for the same session.