Assume successful delivery if no Message Status

It assumes ERROR_CLASS is ERROR_NONE and MSG_STATUS_CODE is
STATUS_DELIVERED if there is no Message Status subparameter in Delivery
Acknowledgment.

Test: Manual

Change-Id: If5660235ce2a6af84d03ec1367a8be5daee672d2
Signed-off-by: Taesu Lee <taesu82.lee@samsung.com>