Tests: unbreak stream_ssl_variables.t with old IO::Socket::SSL.

Do not clobber a stream object in test_tls13().

Author: pluknet

stream_ssl_variables.t

@@ -141,7 +141,7 @@ undef $s;
 ###############################################################################
 
 sub test_tls13 {
-	$s = stream(PeerAddr => '127.0.0.1:' . port(8443), SSL => 1);
+	my $s = stream(PeerAddr => '127.0.0.1:' . port(8443), SSL => 1);
 	$s->read() =~ /TLSv1.3/;
 }