MINOR: quic: Kill the connections on ICMP (port unreachable) packet receipt

The send*() syscall which are responsible of such ICMP packets reception
fails with ECONNREFUSED as errno.

  man(7) udp
  ECONNREFUSED
      No receiver was associated with the destination address.
      This might be caused by a previous packet sent over the socket.

We must kill asap the underlying connection.

Must be backported to 2.7.
3 files changed