ussd: Decode interrogateSS that doesn't have test

Keith of Rhizomatica has an issue of a unrejected interrogateSS.
Start with just decoding the message and printing the empty test
and the code.

What is kind of missing is the classification between invoke,
returnResult and returnResultLast that we need to add in the
long run.

Change-Id: Iadfa156707a96f2a34f3948c7cc9a74435f17114
2 files changed