Improve SMPP supported features and test coverage

esme: Add several bits to handle logic required by tests:
- Allow specifying the mode used to send an sms
- Add a parameter to ask to receive a Delivery receipt for that message
- Add sms_send_wait_resp API, which waits until the response message for
  a given smpp message is received when sending an sms.
- Add receipt_was_received API, which together with
  message_received_handler maintains state of the delivery receipts we
  asked for and were still not received. However, the check needs to be
  disabled for now because OsmoNITB doens't seem to be sending stuff
  properly, see OsmoNITB #2353.
- On message_received_handler, also print alert_notification messages,
  to show that there's actually a bug in OsmoNITB, see #2352.

Move old esme_ms_sms to esme_ms_sms_transaction, and explicitly state
that we are using that mode. On the same test, we can now enable the
part which asserts that sending an SMS to an msisdn with unknown
destination triggers an error. The issue was mainly that the error had
to come from the SMSC server response, not from the sent message, so
we have to wait for the response to have the failure triggered.

Finally, add esme_ms_sms_storeforward, which tests features for sms sent
using that mode, and uses the APIs described above.

Change-Id: Ia2c0c325fee14143deca8310312fc530cd9ce92e
5 files changed