Invalid original_destination_connection_id

[QUICTester]

Hi,

During testing commit 841c822, we discovered that the PQUIC server always updates/overwrites its original_destination_connection_id when processing the client's Initial packet.

According to RFC 9000, original_destination_connection_id is the value of the Destination Connection ID field from the first Initial packet sent by the client. However, when sending the packet sequence below, PQUIC will overwrite the value every time it receives a new Initial packet:

1. Initial packet that carries a Ping frame
2. Initial packet that carries a Ping frame

[mpiraux]

Could you test #39 as a potential fix ?

[QUICTester]

Yes, it is solved.