praekelt/vumi — pull request #771 by jerith (2014-04-22 11:12:44+00:00)
Title: SMPP transport sometimes gives invalid user_message_id in events.

The error looks like:
```
u'Unable to find message for event: '
```
Note the ``'user_message_id': u'None'``

Configuration which produced this has:
```yaml
deliver_short_message_processor_config:
# Because they lie about their unicode encoding
data_coding_overrides:
0: 'utf-8'
8: 'utf-8'

submit_short_message_processor_config:
# allow for multipart SMS delivery
send_multipart_udh: True
```