MINOR: quic: reconnect quic-conn socket on address migration

MINOR: quic: reconnect quic-conn socket on address migration

UDP addresses may change over time for a QUIC connection. When using
quic-conn owned socket, we have to detect address change to break the
bind/connect association on the socket.

For the moment, on change detected, QUIC connection socket is closed and
a new one is opened. In the future, we may improve this by trying to
keep the original socket and reexecute only bind/connect syscalls.

This change is part of quic-conn owned socket implementation.
It may be backported to 2.7 after a period of observation.