Handle localhost being either 127.0.0.1 or ::1

When connecting to "localhost" the Proxy's choice of client address
family may not match the server's choice address family.  Without
MultiHomed => 1, the proxy may try the wrong address family first,
and give up without trying the other.

Reviewed-by: Richard Levitte <levitte@openssl.org>

util/TLSProxy/Proxy.pm

@@ -261,6 +261,7 @@ sub clientstart
         $server_sock = $IP_factory->(
             PeerAddr => $servaddr,
             PeerPort => $self->server_port,
+            MultiHomed => 1,
             Proto => 'tcp'
         );