Clear UTF8 flag from HTTP::Message string. Current libwww (5.810) fails on valid

ASCII strings with UTF8 flag with message like "HTTP::Message content not bytes".

--- lib/RPC/XML/Server.pm

+++ lib/RPC/XML/Server.pm

@@ -70,6 +70,7 @@ use vars qw($VERSION @ISA $INSTANCE $INSTALL_DIR @XPL_PATH

 use Carp 'carp';

 use AutoLoader 'AUTOLOAD';

 use File::Spec;

+use Encode;

 BEGIN {

     $INSTALL_DIR = (File::Spec->splitpath(__FILE__))[1];

@@ -1641,6 +1642,7 @@ sub process_request

                 # Treat the content strictly in-memory

                 $buf = $respxml->as_string;

                 $buf = Compress::Zlib::compress($buf) if $do_compress;

+                Encode::_utf8_off($buf);

                 $resp->content($buf);

                 $resp->content_length($respxml->length);

             }