1) Remove UE Context Release Response code: there is no
such thing in the specs, it is either UE Context Release Request
(NG-RAN node initiated) or UE Context Release (AMF initiated)
(3GPP TS 38.413). The former message has only the request, no
response is defined by the specs. The code in the stack had no
purpose at all and was removed.
2) The UE Context Release Request message only contains a PDU
Session Resource List (optional) of PDU Session IDs, therefore
the use of pdusession_release_t was wrong and was refactored
Guido Casati
ad1c92af4f