daemon: use unpack_sockaddr_* for clarity

daemon: use unpack_sockaddr_* for clarity

unpack_sockaddr_un and unpack_sockaddr_in have been around since
Perl 5.002 in the mid-1990s, so be explicit and use them instead
of relying on wantarray caller context.  We'll also omit the
$host check for ($port == 0) since zero is not a valid TCP port.