MEDIUM: sock: also restore effective unix family in get_{src,dst}()

MEDIUM: sock: also restore effective unix family in get_{src,dst}()

As in previous commit, let's push the logic a bit further in order to
properly restore the effective UNIX socket type when leveraging
get_src() and get_dst() sock functions, since they rely on getpeername()
and getsockname() under the hood, both of which will actually loose the
effective family and return AF_UNIX for all our custom UNIX sockets.

To do this, add sock_restore_unix_family() helper function from the logic
implemented in the previous commit, and call this function from get_src()
and get_dst() in case of unix socket prior to returning.