Fix the issue that asterisk crash during some auto-test

The issue original comes from the stage after the "multi-line appearance" test and before the "speed dial" test, combined with different environment changes including network, config and different services reload.

Direct reason leading to this crash is the SIP un-registration request(during asterisk shutdown, or network re-connection) got an 200 OK with expiration value which is not 0(due to the server setting and network), and asterisk is handle this response as registration success based on the expiration value is not 0, which made the other steps followed went into uncontrollable stage(unstoppable loop of the un-registration requests until core crash).

Retrieve the requested expiration if possible, and check it combined with the received expiration to identify if the 200 OK response is regards to registering or unregistering