Bug in strict route processing when challenged with 401/407 response (thanks Klaus Darilion)

[bennylp]

Quoting Klaus email:

If I specify an outbound proxy (acc_cfg) as strict router (no "lr" parameter), then I observe the following behavior:

1. pjsua send REGISTER to outbound proxy (RURI and ROUTE is swapped due to strict routing) --> correct
2. pjsua receives 401
3. pjsua resend the REGISTER with credentials, but it send it directly to the registrar (RURI and ROUTE are either "not swapped" or "swapped twice") --> Bug

This is because when PJSIP reinitialize the request to handle authentication challenge, it reuses the original SIP request, and while doing so it doesn't restore the Route header (for the strict route) to the original order. So when the request is sent, PJSIP will swap the Route header again because it detects strict route in the request.

[bennylp]

Fixed in r1816