Avoid termination of unknown sessions

[javiermtorres]

erGW-AAA version

4.3.1

Erlang/OTP version

N/A

Description

• Motivation
  Failures of Gy updates with reason code UNKNOWN_SESSION_ID (5002) trigger a termination CCR with the same session ID. This message will (naturally) be answered with another 5002 from the OCS.

• Proposal
  If a 5002 message is received for a session, consider that the session has ended locally and do not send a followup termination CCR.