Session shuts down if multiple HARD_RESET received during handshake

[keeshux]

With a .staleSession error.

Regression in 0f2234f

[keeshux]

22:42:28 - Send hard reset
22:42:28 - Negotiation key index is 0
22:42:28 - Control: Enqueued 1 packet [0]
22:42:28 - Control: Write control packet {HARD_RESET_CLIENT_V2 | 0, sid: 79d4e916ac049a60, pid: 0, [0 bytes]}
22:42:28 - Send control packet (14 bytes): 3879d4e916ac049a600000000000
22:42:28 - Control: Try read packet with code HARD_RESET_SERVER_V2 and key 0
22:42:28 - Control: Read packet {HARD_RESET_SERVER_V2 | 0, sid: 4f8c808678cf0e15, pid: 0}
22:42:28 - Send ack for received packetId 0
22:42:28 - Control: Write ack packet {ACK_V1 | 0, sid: 79d4e916ac049a60, acks: {[0], 4f8c808678cf0e15}}
22:42:28 - Control: Remote sessionId is 4f8c808678cf0e15
22:42:28 - Start TLS handshake
22:42:28 - TLS.connect: Pulled ciphertext (176 bytes)
22:42:28 - Control: Enqueued 1 packet [1]
22:42:28 - Control: Skip writing packet with packetId 0 (sent on 2019-09-01 21:42:28 +0000, 0.05271291732788086 seconds ago)
22:42:28 - Control: Write control packet {CONTROL_V1 | 0, sid: 79d4e916ac049a60, pid: 1, [176 bytes]}

22:42:28 - Send control packet (190 bytes): 2079d4e916ac049a60000000000116030100ab010000a70303cfef0e29963558535211afcd9ffa7b75bc02e5aae6cc848d95cdf5f4a02d7a11000038c02cc030009fcca9cca8ccaac02bc02f009ec024c028006bc023c0270067c00ac0140039c009c0130033009d009c003d003c0035002f00ff01000046000b000403000102000a000a0008001d001700190018002300000016000000170000000d0020001e060106020603050105020503040104020403030103020303020102020203
22:42:28 - Ack successfully written to LINK for packetId 0
22:42:28 - Control: Try read packet with code HARD_RESET_SERVER_V2 and key 0
22:42:28 - Control: Read packet {HARD_RESET_SERVER_V2 | 0, sid: 4f8c808678cf0e15, acks: {[0], 79d4e916ac049a60}, pid: 0}
22:42:28 - Trigger shutdown (error: staleSession)
22:42:28 - Session did stop
22:42:28 - Failed LINK read: Error Domain=kNWErrorDomainPOSIX Code=89 "Operation canceled" UserInfo={NSDescription=Operation canceled}
22:42:28 - Socket state is cancelled (endpoint: <masked> -> in progress)
22:42:28 - Cleaning up...
22:42:28 - Tunnel did stop (error: staleSession)
22:42:28 - Flushing log...