Fix hxtool.

When converting from hx to texi format, hxtool (or to be
more precise sh which interprets hxtool) used standard
shell expansion of wildcards while writing lines to the
output.

Thus, something like "Password: ********"
looked very different in the generated documentation.

The patch disables this unwanted wildcard expansion.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
